Vibration Situation of Long Duration Causing Great Consternation
10-04-2016, 07:33 AM
#1
Vibration Situation of Long Duration Causing Great Consternation
So I have an '89 Firebird Formula.
111,000 miles
L03 / T5
I bought the car new, and have never (overly) abused it. It has always driven smoothly.
It is stock, with four exceptions.
It came with a 3.08 open differential. About 25,000 miles ago, I had a 3.42 gear and a Zexel-Torsen limited slip installed. There were no problems with the installation, and there were no vibration problems at all.
About 20,000 miles ago, the original, factory clutch began to slip. I replaced it with a Centerforce clutch kit. The flywheel was resurfaced. Everything was fine afterwards; no vibrations.
At around the same time, I installed a custom, mandrel-bent exhaust system. Again, no vibration(s).
At around the same time, I also installed Lakewood tubular control arms, KYB shocks and struts, and a complete Energy Suspension Polyurethane bushing kit, front and rear. No vibrations.
Around 10,000 miles ago, the car suddenly began vibrating at around 70mph. Beyond that, the faster you went, the worse the vibration got. I hadn't changed anything on the car for more than 10,000 miles.
I had the tires checked for true and balance; no change.
I took it to a driveline shop. He said the universal joints were bad, so I had him install new Spicer front and rear u-joints. No change.
Took it back. He said the driveshaft was twisted. I bought an aluminum driveshaft out of a 2001 LS1 Camaro, took it to a local driveshaft shop, had it checked for true and balanced (without the donut), and installed it. The vibration was unchanged.
Had the driveshaft balance checked by another driveshaft shop. It was dead on. The vibration was unchanged.
One day, I was sitting parked in the driveway with the transmission in neutral, and slowly revved the engine up. Starting at around 1,800 rpm, until about 2,400 rpm, it vibrated pretty significantly.
This was puzzling. In 5th gear, at 70 mph, the car is doing right at 2,200 rpm, so it makes sense that the engine vibration is causing it. What doesn't make sense is, the faster you go, the worse the vibration gets. When it vibrates while sitting still, with the transmission in neutral, the vibration tapers off after 2,500 rpm. What's more, when driving down the road at 70 mph, with the car vibrating, I can throw it up into neutral, and it still vibrates until the speed drops down to below 65, or so ... the engine is idling! I can run it up till it starts vibrating at 70 mph, throw it in neutral, and shut the engine completely off, and it still vibrates. The vibration actually gets worse at first, as soon as you put it in neutral, then it tapers off as you slow down.
I came to the conclusion that I had two separate vibrations. I decided to focus on the engine vibration.
I took the fan belt off of it . With them not turning, that would eliminate the alternator, power steering pump, water pump, air pump, etc as causal. The vibration was unchanged.
I put a new, stock harmonic balancer on it. The vibration was unchanged.
Every time I'd talk to someone new about the problem, they'd tell me I had to start back at square-one, so I'd have the tires re-balanced, and the driveshaft re-balanced. It was utterly demoralizing, and expensive.
I got disgusted, and decided to park the car; the vibration was getting progressively worse, and I'd already thrown over a grand at the problem, with no resolution in sight.
Well, that turned into seven years with the car parked in my garage.
Last fall, I put the car back on the road, and got back to lighting money on fire trying to find the vibration(s). The tires had dry rotted and separated, so I replaced them with new ones. I had the wheels checked for true when they were being balanced. They were fine. The vibrations were unchanged.
At the insistence of my mechanic, I had the driveshaft balanced again; this time up to 150 mph, not 80. No change in the vibration(s)
My mechanic put the car up on the rack, and we disconnected the control arms, torque arm, panhard bar and rear shocks and checked the bushings. They were all good. We ran the car on the rack until it vibrated (I know, I know). We could hear a bearing in the transmission squealing intermittently. Loudly. You couldn't hear it in the car, but listening to it up on the rack, it was alarming. The transmission shifted perfectly, but a squealing bearing probably eventually turns into a seized bearing, and I wanted to get it fixed before that happened, and did real damage.
We asked around for the best transmission shop in the area. One guy's name kept coming up. I took the car to him and let him check it out. He said he had a piece of diagnostic equipment called "Chassis Ears" which would allow him to isolate the causes of the vibrations. He said he'd put the Chassis Ears on it, then pull the transmission, tear it down, and call me.
He called me the next day, telling me the transmission just needed a refresh; new bearings, seals and synchros, and the Chassis Ears had indicated the clutch was bad. He said he'd pulled it off, and he could see where the balancing weights were out of whack, so he'd replaced the clutch, had the flywheel balanced and turned, and then had the new clutch balanced on the flywheel.
I went to pick the car up, and the vibrations were exactly as before.
I'm not going to go into detail over all the problems with the shop. It's covered in another thread. I'm still battling with them, lawyers are involved, and it'll probably be a couple of months before it's resolved. There are two key elements, though:
1) I sent my old clutch back to Centerforce. Their engineer said there was nothing wrong with it. More importantly, he said there were signs the release bearing had been coming into contact with the balancing weights, which suggested an out-of-balance condition. Since the balance on the clutch had checked out perfectly, he said I should look at the flywheel.
2) After much back-and-forth, the transmission guy finally admitted not only had he not had the flywheel balanced, he hadn't had it resurfaced, either. He'd never taken it off the car.
This definitely leads me to suspect the flywheel is the culprit in the case of the engine vibration. The transmission isn't right, and it's going to have to come back out. When it does, I'm going to have the flywheel trued and balanced, and have my original Centerforce clutch balanced to the flywheel, and put back on the car.
That won't address the chassis vibration, though. When he'd rebuilt the transmission, the transmission guy had put a new transmission mount on the car, and told me the engine mounts were bad, too. After I got it back, I inspected them. Even though the driveline angles were dead-on, they did look a little sketchy, so I had them replaced. At the same time, I had the rearend gone through; all new bearings and seals, and the ring and pinion setup checked.
Something changed. The car still vibrates, but before, where it would start at around 70, and get worse as you went faster, now it starts at 70, but begins to taper off at around 80mph, and remains constant as you go faster and faster. It's vibrating at a much less severe level than before at high speed.
"A-HA!" You say. New motor mounts and rebuilding the rearend resolved the driveline vibration!"
Well, not exactly. As before, if you get up to 70, where it starts vibrating, throw it up in neutral and shut the engine off, and it vibrates until it gets down to about 60. That can't be an engine vibration.
Wait, there's more! Now, sometimes it starts vibrating at 60, instead of 70. Sometimes it doesn't. Sometimes it barely vibrates at all, even at 70. Sometimes it's almost as bad as before.
Maybe I have/had three vibrations.
I'm totally, completely, absolutely, utterly exhausted, and out of things to replace.
Can anyone help?
Thanks.
111,000 miles
L03 / T5
I bought the car new, and have never (overly) abused it. It has always driven smoothly.
It is stock, with four exceptions.
It came with a 3.08 open differential. About 25,000 miles ago, I had a 3.42 gear and a Zexel-Torsen limited slip installed. There were no problems with the installation, and there were no vibration problems at all.
About 20,000 miles ago, the original, factory clutch began to slip. I replaced it with a Centerforce clutch kit. The flywheel was resurfaced. Everything was fine afterwards; no vibrations.
At around the same time, I installed a custom, mandrel-bent exhaust system. Again, no vibration(s).
At around the same time, I also installed Lakewood tubular control arms, KYB shocks and struts, and a complete Energy Suspension Polyurethane bushing kit, front and rear. No vibrations.
Around 10,000 miles ago, the car suddenly began vibrating at around 70mph. Beyond that, the faster you went, the worse the vibration got. I hadn't changed anything on the car for more than 10,000 miles.
I had the tires checked for true and balance; no change.
I took it to a driveline shop. He said the universal joints were bad, so I had him install new Spicer front and rear u-joints. No change.
Took it back. He said the driveshaft was twisted. I bought an aluminum driveshaft out of a 2001 LS1 Camaro, took it to a local driveshaft shop, had it checked for true and balanced (without the donut), and installed it. The vibration was unchanged.
Had the driveshaft balance checked by another driveshaft shop. It was dead on. The vibration was unchanged.
One day, I was sitting parked in the driveway with the transmission in neutral, and slowly revved the engine up. Starting at around 1,800 rpm, until about 2,400 rpm, it vibrated pretty significantly.
This was puzzling. In 5th gear, at 70 mph, the car is doing right at 2,200 rpm, so it makes sense that the engine vibration is causing it. What doesn't make sense is, the faster you go, the worse the vibration gets. When it vibrates while sitting still, with the transmission in neutral, the vibration tapers off after 2,500 rpm. What's more, when driving down the road at 70 mph, with the car vibrating, I can throw it up into neutral, and it still vibrates until the speed drops down to below 65, or so ... the engine is idling! I can run it up till it starts vibrating at 70 mph, throw it in neutral, and shut the engine completely off, and it still vibrates. The vibration actually gets worse at first, as soon as you put it in neutral, then it tapers off as you slow down.
I came to the conclusion that I had two separate vibrations. I decided to focus on the engine vibration.
I took the fan belt off of it . With them not turning, that would eliminate the alternator, power steering pump, water pump, air pump, etc as causal. The vibration was unchanged.
I put a new, stock harmonic balancer on it. The vibration was unchanged.
Every time I'd talk to someone new about the problem, they'd tell me I had to start back at square-one, so I'd have the tires re-balanced, and the driveshaft re-balanced. It was utterly demoralizing, and expensive.
I got disgusted, and decided to park the car; the vibration was getting progressively worse, and I'd already thrown over a grand at the problem, with no resolution in sight.
Well, that turned into seven years with the car parked in my garage.
Last fall, I put the car back on the road, and got back to lighting money on fire trying to find the vibration(s). The tires had dry rotted and separated, so I replaced them with new ones. I had the wheels checked for true when they were being balanced. They were fine. The vibrations were unchanged.
At the insistence of my mechanic, I had the driveshaft balanced again; this time up to 150 mph, not 80. No change in the vibration(s)
My mechanic put the car up on the rack, and we disconnected the control arms, torque arm, panhard bar and rear shocks and checked the bushings. They were all good. We ran the car on the rack until it vibrated (I know, I know). We could hear a bearing in the transmission squealing intermittently. Loudly. You couldn't hear it in the car, but listening to it up on the rack, it was alarming. The transmission shifted perfectly, but a squealing bearing probably eventually turns into a seized bearing, and I wanted to get it fixed before that happened, and did real damage.
We asked around for the best transmission shop in the area. One guy's name kept coming up. I took the car to him and let him check it out. He said he had a piece of diagnostic equipment called "Chassis Ears" which would allow him to isolate the causes of the vibrations. He said he'd put the Chassis Ears on it, then pull the transmission, tear it down, and call me.
He called me the next day, telling me the transmission just needed a refresh; new bearings, seals and synchros, and the Chassis Ears had indicated the clutch was bad. He said he'd pulled it off, and he could see where the balancing weights were out of whack, so he'd replaced the clutch, had the flywheel balanced and turned, and then had the new clutch balanced on the flywheel.
I went to pick the car up, and the vibrations were exactly as before.
I'm not going to go into detail over all the problems with the shop. It's covered in another thread. I'm still battling with them, lawyers are involved, and it'll probably be a couple of months before it's resolved. There are two key elements, though:
1) I sent my old clutch back to Centerforce. Their engineer said there was nothing wrong with it. More importantly, he said there were signs the release bearing had been coming into contact with the balancing weights, which suggested an out-of-balance condition. Since the balance on the clutch had checked out perfectly, he said I should look at the flywheel.
2) After much back-and-forth, the transmission guy finally admitted not only had he not had the flywheel balanced, he hadn't had it resurfaced, either. He'd never taken it off the car.
This definitely leads me to suspect the flywheel is the culprit in the case of the engine vibration. The transmission isn't right, and it's going to have to come back out. When it does, I'm going to have the flywheel trued and balanced, and have my original Centerforce clutch balanced to the flywheel, and put back on the car.
That won't address the chassis vibration, though. When he'd rebuilt the transmission, the transmission guy had put a new transmission mount on the car, and told me the engine mounts were bad, too. After I got it back, I inspected them. Even though the driveline angles were dead-on, they did look a little sketchy, so I had them replaced. At the same time, I had the rearend gone through; all new bearings and seals, and the ring and pinion setup checked.
Something changed. The car still vibrates, but before, where it would start at around 70, and get worse as you went faster, now it starts at 70, but begins to taper off at around 80mph, and remains constant as you go faster and faster. It's vibrating at a much less severe level than before at high speed.
"A-HA!" You say. New motor mounts and rebuilding the rearend resolved the driveline vibration!"
Well, not exactly. As before, if you get up to 70, where it starts vibrating, throw it up in neutral and shut the engine off, and it vibrates until it gets down to about 60. That can't be an engine vibration.
Wait, there's more! Now, sometimes it starts vibrating at 60, instead of 70. Sometimes it doesn't. Sometimes it barely vibrates at all, even at 70. Sometimes it's almost as bad as before.
Maybe I have/had three vibrations.
I'm totally, completely, absolutely, utterly exhausted, and out of things to replace.
Can anyone help?
Thanks.
10-04-2016, 08:12 AM
#2
Re: Vibration Situation of Long Duration Causing Great Consternation
Well, as you now know, Chassis Ears is not a vibration analyzer. GM had all dealers switch from EVA to the Pico Scope for their vibration analysis tool a couple of years ago. If you can find a dealer that is very knowledgeable and comfortable with that tool, they will find your vibration. Or, if you can find an older tech with a reed tach, they can help pinpoint your vibration also. Unfortunately, some Chevy and GMC trucks have had some difficult vibrations in the last few years, so I would suggest checking with some Chevy or GMC dealers local to you.
10-04-2016, 08:27 AM
#3
Re: Vibration Situation of Long Duration Causing Great Consternation
Well, as you now know, Chassis Ears is not a vibration analyzer. GM had all dealers switch from EVA to the Pico Scope for their vibration analysis tool a couple of years ago. If you can find a dealer that is very knowledgeable and comfortable with that tool, they will find your vibration. Or, if you can find an older tech with a reed tach, they can help pinpoint your vibration also. Unfortunately, some Chevy and GMC trucks have had some difficult vibrations in the last few years, so I would suggest checking with some Chevy or GMC dealers local to you.
Finally, he told me GM had supplied all their dealers with Picoscope NVHs several years ago. I've been in contact with 5 GM dealerships' service managers so far. 2 had no idea what I was talking about; 3 said they have them, but GM never gave them any training on them, and they hadn't even unboxed them yet.
10-04-2016, 10:35 AM
#4
Re: Vibration Situation of Long Duration Causing Great Consternation
Thanks. I'd found the Picoscope NVH in my searching for a solution. I contacted Pico and asked if they could refer me to a shop in my area that had one. The guy was pretty rude, simply repeating he could not give out customer information over and over.
Finally, he told me GM had supplied all their dealers with Picoscope NVHs several years ago. I've been in contact with 5 GM dealerships' service managers so far. 2 had no idea what I was talking about; 3 said they have them, but GM never gave them any training on them, and they hadn't even unboxed them yet.
Finally, he told me GM had supplied all their dealers with Picoscope NVHs several years ago. I've been in contact with 5 GM dealerships' service managers so far. 2 had no idea what I was talking about; 3 said they have them, but GM never gave them any training on them, and they hadn't even unboxed them yet.
http://sandyblogs.com/techlink/?p=4689
Regardless I wouldn't want to pay to be the guinea pig if they really aren't familiar with the tool yet. I would guess that you either talked to uninformed managers, or someone that was looking for a way out of not working on an older vehicle. You might search other truck forums (Silverado / Sierra) and see if people are recommending any dealer close to you. That tool is really great if you can find someone that knows how to use it.
10-05-2016, 10:01 AM
#6
Member
Re: Vibration Situation of Long Duration Causing Great Consternation
I went through this many years ago with a ford LTD, chased an engine vibration for two years to no avail. The car was involved in a crash and I parted it out, my cousin was going to rebuild the engine and put it in his pickup, but when we tore it down we found the crankshaft cracked in half. The crack ran at an angle that kept the two halves from getting more than just barely out of alignment with each other, but of course it caused the engine to vibe just like it had a bad harmonic balancer. Never seen that before or since, so it's pretty rare thank goodness.
10-05-2016, 11:38 AM
#7
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Re: Vibration Situation of Long Duration Causing Great Consternation
Is the vibration always there? If you put the car in neutral when its vibrating does it stop?
Never mentioned the condition of the pilot bearing?
If it was solely based on rpm, you would have the vibe in all gears at any speed when you reach that rpm.
Never mentioned the condition of the pilot bearing?
If it was solely based on rpm, you would have the vibe in all gears at any speed when you reach that rpm.
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10-05-2016, 01:07 PM
#8
Supreme Member
Re: Vibration Situation of Long Duration Causing Great Consternation
Well, not exactly. As before, if you get up to 70, where it starts vibrating, throw it up in neutral and shut the engine off, and it vibrates until it gets down to about 60. That can't be an engine vibration.
How are your rear brakes, I had a set that were partially seized and vibe would come and go regularly
10-05-2016, 06:08 PM
#9
Senior Member
Re: Vibration Situation of Long Duration Causing Great Consternation
Wheres the "lawyers involved" thread?
10-05-2016, 07:25 PM
#10
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Re: Vibration Situation of Long Duration Causing Great Consternation
Change the extension housing bushing.
10-06-2016, 12:36 AM
#11
Re: Vibration Situation of Long Duration Causing Great Consternation
If I'm sitting with the car parked, in neutral, and slowly rev it up, it starts vibrating at about 1,800 rpm, peaks at 2,200-2,300, and tapers off at around 2,500.
When I'm running down the road and hit the speed where it starts vibrating, though, I can put it in neutral; even shut the engine off, and the vibration actually gets worse, until it starts to taper off as the car slows down.
That leads me to believe I have a chassis vibration, AND an engine vibration.
That's complicated. I mentioned the transmission rebuild from hell, that's ending up in court ....
Well, the pilot bearing was supposed to have been replaced as part of the clutch replacement they did, but they didn't turn the flywheel, or balance it, as they said they had (and charged me for), so there's no way to be sure they replaced the pilot bearing.
So in the massive drama-fest that ensued after the transmission rebuild by Shop #1, there were serious problems with the transmission. The release bearing made a loud, grinding noise whenever it was in neutral, with the motor running, and the clutch was disengaged. Push the pedal in, and the noise went away.
You know the synchronizer whine you get when you downshift into 1st while the car is moving? Mine was doing that on every downshift. LOUDLY. It also made the noise while idling along in 1st, or 2nd gear.
The transmission was very "notchy". It took a lot more effort than before on every shift. The synchronizers would intermittently scrape on the 2-3, 3-4, and 4-5 upshifts. When the car was cold, it scrapes every time on the 4-5 upshift if you wind it out a bit.
As I drove the car, the transmission problems got progressively worse. It finally reached a point where it just sat there and shook in neutral.
I'd disputed the charge for the transmission rebuild with my credit card company. Part of that process involved getting a written opinion and estimate from another shop (heretofore referred to as "Shop #2). I'd been pleading with Shop #2 to get to my Firebird. When it reached a point of being completely undriveable, he finally agreed, promising he's get it up on the rack "tomorrow".
I chased him for 7 weeks to work on it. When he finally got the car up on the rack, he discovered the bolts holding the transmission in were loose, and there was a 1 to 1 1/2-inch gap between the transmission and the bellhousing. Shop #2 guy told me he believed the transmission had been slowly working itself looser and looser every time I pushed the clutch pedal in, which explained why the problems had been getting progressively worse.
For reasons I will never understand, instead of tightening the transmission bolts back up and test driving the car to see what effect that had on the problems, he went ahead and pulled the transmission.
And it sat .... and sat ... and sat.
After pleading with him to fix the car virtually every day for over three weeks, I got a letter from my credit card company saying the deadline for the deal I'd negotiated to get my car fixed had expired, and my dispute of the transaction with Shop #1 had been denied. I was out $1,260.
I was not happy. I went over to shop #2 and demanded he put my car back together ... INSTANTLY!. He was somewhat reluctant at first, but I persuaded him. Let's just say some days it pays to be 6'5", 280, and a former kinda badass.
I literally stood over him as he put it back together. Suddenly, he was wanting to fix it, asking if I wanted him to have the flywheel resurfaced and balanced, etc. I would have none of it, telling him I was done with him, and just wanted my car put back together as it had been when I left it with him.
He pointed the pilot bearing out to me. It was brass, and was clearly wallowed out. He said it was from the transmission being loose, and moving around. He said he had one right there, and he'd be uncomfortable not replacing it, so I let him.
So, the short answer is, the pilot bearing was shot, but I don't know if that's the pilot bearing that was put in the car when I had the Centerforce clutch put in 20,000 miles ago, or if Shop #1 put it in when they rebuilt the transmission. Therefore, I don't know how much of the wallowing out of the pilot bearing was caused by the ongoing vibration problem, problems with the transmission rebuild Shop #1 did, or problems caused by Shop #1s apparent failure to tighten up the four bolts connecting the transmission to the bellhousing.
After I got the car back from Shop #2, with the only changes being the transmission is now bolted securely to the bellhousing, and the pilot bearing has been replaced, the problems with the transmission are not nearly as bad, but are still there.
So, now you know how I spent my summer. How was yours?
It's hard to tell in 1st and 2nd, but in 3rd and 4th, it definitely vibrates in that 1,800 - 2,500 rpm range.
10-06-2016, 12:42 AM
#13
Re: Vibration Situation of Long Duration Causing Great Consternation
10-06-2016, 01:33 AM
#14
Re: Vibration Situation of Long Duration Causing Great Consternation
The extension housing is the tailshaft housing, isn't it?
If so, It was supposed to have been replaced when the transmission was rebuilt.
As I was writing that, it occurred to me that the shop that rebuilt the transmission doesn't have a very good record when it comes to doing what they were supposed to do.
Is there a test to see if it is bad?
If so, It was supposed to have been replaced when the transmission was rebuilt.
As I was writing that, it occurred to me that the shop that rebuilt the transmission doesn't have a very good record when it comes to doing what they were supposed to do.
Is there a test to see if it is bad?
10-06-2016, 06:50 AM
#15
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Re: Vibration Situation of Long Duration Causing Great Consternation
Is there a test to see if it is bad?
For sure though, you shouldn't be able to move the drive shaft yoke inside it. If it doesn't fit tight, it's wore out.
Only costs like $1. Same one fits a T-350.
Find a shop that has the tools that can change it out without disassembling anything. Takes a puller with thin fingers that can reach into there around the mainshaft and then a pipe-like installer.
10-06-2016, 07:17 PM
#16
Senior Member
Re: Vibration Situation of Long Duration Causing Great Consternation
When you go to court would you mind recording it? Like with a laptop the same way I recorded my "Eds CROOKS" videos.
10-06-2016, 11:52 PM
#18
Re: Vibration Situation of Long Duration Causing Great Consternation
You can put an app on your phone to tell what frequency the vibe is.
Tires are going to be within a range.
Driveshaft will be in a relative range.
The only hassle is getting the app. set up to read within the right high & low range.
Tires are going to be within a range.
Driveshaft will be in a relative range.
The only hassle is getting the app. set up to read within the right high & low range.
10-06-2016, 11:58 PM
#19
Re: Vibration Situation of Long Duration Causing Great Consternation
Do you know what the app is?
I've been chasing a driveline vibration analyzer called a PicoScope NVH. GM switched all of their dealerships over to it a couple of years ago, but every service department I've contacted says they have it, but no one's been trained on it, and they haven't even unboxed it yet.
I've been chasing a driveline vibration analyzer called a PicoScope NVH. GM switched all of their dealerships over to it a couple of years ago, but every service department I've contacted says they have it, but no one's been trained on it, and they haven't even unboxed it yet.
10-07-2016, 05:04 AM
#20
Re: Vibration Situation of Long Duration Causing Great Consternation
I would be leary of any such phone app. With a real vibration analyzer, you can greatly affect the reading simply by changing the sensor orientation or location. No way a phone is ever going to give you the accuracy you want after chasing this as long as you already have.
Last edited by Lurbie; 10-07-2016 at 05:55 AM.
10-07-2016, 05:15 AM
#21
Re: Vibration Situation of Long Duration Causing Great Consternation
I would be leary of an such phone app. With a really vibration analyzer, you can greatly affect the reading simply by changing the sensor orientation or location. No way a phone is ever going to give you the accuracy you want after chasing this as long as you already have.
10-07-2016, 06:00 PM
#24
Re: Vibration Situation of Long Duration Causing Great Consternation
I sure wish the forum's mobile app showed locations. I was on my laptop tonight and realized you're in Tulsa. I know someone there and after contacting them, I sent you a private message with some contact information.
10-07-2016, 07:02 PM
#26
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Re: Vibration Situation of Long Duration Causing Great Consternation
This is going to sound silly but it's actually a fact. I chased a vibration for years going through the same hassle with tires, wheels, transmission, drive train angle, driveshaft, clutch and so on...
When you rev the engine while the car is parked, your exhaust could cause a vibration depending on the frequency (vibration #1). This happens with modifications, specially the exhaust. When I switched my SLP exhaust to a Magnaflow, I got a light vibration between 3000-3500 rpm with the car sitting clutch depressed in neutral. With the new Hooker now it's better but still noticable.
When I was coasting in 5th gear at around 3000 rpm and up (70mph and up) there was a nasty vibration too, strong pulsation type with fast amplitude (vibration #2). It would not do it in 4th or 6th gear at the same speed (different rpm!). I suspected the transmission but I came to find out that the Magnaflow exhaust's pulsation would change its amplitude depending on speed/rpm. So if I would drive the car up to let's say 75mph in 5th gear at a bit over 3000rpm, the pulsation would be strong and fast. The car would vibrate a lot. I would simply depress the clutch, get out of gear (neutral) and hold the engine at 3200 rpm while coasting. The vibration would still be there. As the vehicle would slow down, the pulsation amplitude would get longer and lighter until it would reach the same as when the vehicle was parked (vibration #1). The effect was just like 2 guitar strings out of tune. As you turn the tuning nub, the pulsation goes from fast to slow until it disappears meaning they are in tune.
With the new hooker, the vibration has diminished a lot over 70mph. I guess this is all about sound wave and speed.
Also, if I would let the car coast in neutral over 70mph, I would get a vibration that would diminish as the vehicle would slow down (vibration #3). That was a different vibration. I came to find out that as I put the car in neutral and coast at high speed, the drive train would vibrate. If, while in gear, I accelerate, decelerate or coast normally I don't get vibration, only when in neutral. I don't really have an explanation for it other than the driveline does not like coasting in neutral at high speed!!!
And finally, as my car sits a lot with drag radials, the tire run out gets out of whack. The balancer won't correct that. This creates a mild vibration (vibration #4) and high speed. The steering wheel is not vibrating from right to left but instead shaking up and down with the rest of the car.
That's my 2 cents worth.
Good luck
When you rev the engine while the car is parked, your exhaust could cause a vibration depending on the frequency (vibration #1). This happens with modifications, specially the exhaust. When I switched my SLP exhaust to a Magnaflow, I got a light vibration between 3000-3500 rpm with the car sitting clutch depressed in neutral. With the new Hooker now it's better but still noticable.
When I was coasting in 5th gear at around 3000 rpm and up (70mph and up) there was a nasty vibration too, strong pulsation type with fast amplitude (vibration #2). It would not do it in 4th or 6th gear at the same speed (different rpm!). I suspected the transmission but I came to find out that the Magnaflow exhaust's pulsation would change its amplitude depending on speed/rpm. So if I would drive the car up to let's say 75mph in 5th gear at a bit over 3000rpm, the pulsation would be strong and fast. The car would vibrate a lot. I would simply depress the clutch, get out of gear (neutral) and hold the engine at 3200 rpm while coasting. The vibration would still be there. As the vehicle would slow down, the pulsation amplitude would get longer and lighter until it would reach the same as when the vehicle was parked (vibration #1). The effect was just like 2 guitar strings out of tune. As you turn the tuning nub, the pulsation goes from fast to slow until it disappears meaning they are in tune.
With the new hooker, the vibration has diminished a lot over 70mph. I guess this is all about sound wave and speed.
Also, if I would let the car coast in neutral over 70mph, I would get a vibration that would diminish as the vehicle would slow down (vibration #3). That was a different vibration. I came to find out that as I put the car in neutral and coast at high speed, the drive train would vibrate. If, while in gear, I accelerate, decelerate or coast normally I don't get vibration, only when in neutral. I don't really have an explanation for it other than the driveline does not like coasting in neutral at high speed!!!
And finally, as my car sits a lot with drag radials, the tire run out gets out of whack. The balancer won't correct that. This creates a mild vibration (vibration #4) and high speed. The steering wheel is not vibrating from right to left but instead shaking up and down with the rest of the car.
That's my 2 cents worth.
Good luck
Last edited by SbFormula; 10-07-2016 at 07:21 PM.
10-07-2016, 07:30 PM
#28
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Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Vibration Situation of Long Duration Causing Great Consternation
Like, at highway speed, when you only roll down a back window half way on a sedan with the rest of the windows up and you feel that pulsation in your ear and chest.
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabilizes.
No one has ever figured out my vibration problem because everyone was focusing on drivetrain, wheels and everything that turns. Sound waves and harmonics can be bad if not synchronized. Engineers when they design a car have to look into that. When we modify, we make the engine sound wave different and also make parts turning in different ratios than originally designed.
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabilizes.
No one has ever figured out my vibration problem because everyone was focusing on drivetrain, wheels and everything that turns. Sound waves and harmonics can be bad if not synchronized. Engineers when they design a car have to look into that. When we modify, we make the engine sound wave different and also make parts turning in different ratios than originally designed.
Last edited by SbFormula; 10-07-2016 at 07:35 PM.
10-07-2016, 07:33 PM
#29
Re: Vibration Situation of Long Duration Causing Great Consternation
Like, at highway speed, when you only roll down a back window half way on a sedan with the rest of the windows up and you feel that pulsation in your ear and chest.
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabalizes
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabalizes
10-07-2016, 07:38 PM
#30
Supreme Member
Join Date: Jun 2012
Location: Canada
Posts: 1,225
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Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Vibration Situation of Long Duration Causing Great Consternation
Check This out
10-07-2016, 07:57 PM
#33
Re: Vibration Situation of Long Duration Causing Great Consternation
Like, at highway speed, when you only roll down a back window half way on a sedan with the rest of the windows up and you feel that pulsation in your ear and chest.
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabilizes.
No one has ever figured out my vibration problem because everyone was focusing on drivetrain, wheels and everything that turns. Sound waves and harmonics can be bad if not synchronized. Engineers when they design a car have to look into that. When we modify, we make the engine sound wave different and also make parts turning in different ratios than originally designed.
It was not humming like a guitar but had the same feeling of 2 strings out of tune coming back in tune. The amplitude getting longer and longer until it stabilizes.
No one has ever figured out my vibration problem because everyone was focusing on drivetrain, wheels and everything that turns. Sound waves and harmonics can be bad if not synchronized. Engineers when they design a car have to look into that. When we modify, we make the engine sound wave different and also make parts turning in different ratios than originally designed.
10-07-2016, 07:58 PM
#34
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Join Date: Jun 2012
Location: Canada
Posts: 1,225
Received 149 Likes
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Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Vibration Situation of Long Duration Causing Great Consternation
10-07-2016, 08:03 PM
#35
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Join Date: Jun 2012
Location: Canada
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Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Vibration Situation of Long Duration Causing Great Consternation
I could hear it through the floor pan... the bastard was thumping hard. I never liked the Magnaflow anyway so the Hooker is way better to my taste. For my TPI set up it vibrates between 3000-3500 rpm
Last edited by SbFormula; 10-07-2016 at 08:08 PM.
10-07-2016, 08:39 PM
#36
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Join Date: Jun 2012
Location: Canada
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Car: '91 Firebird Formula
Engine: SP383 Deluxe FIRST® TPI Intake
Transmission: Tremec T56
Axle/Gears: Moser 9" Eaton Truetrac Motive 3.89
Re: Vibration Situation of Long Duration Causing Great Consternation
I just read the entire forum and notice you had originally posted this:
"This definitely leads me to suspect the flywheel is the culprit in the case of the engine vibration. The transmission isn't right, and it's going to have to come back out. When it does, I'm going to have the flywheel trued and balanced, and have my original Centerforce clutch balanced to the flywheel, and put back on the car."
I was not aware this still needed to be addressed. That could be your problem too.
"This definitely leads me to suspect the flywheel is the culprit in the case of the engine vibration. The transmission isn't right, and it's going to have to come back out. When it does, I'm going to have the flywheel trued and balanced, and have my original Centerforce clutch balanced to the flywheel, and put back on the car."
I was not aware this still needed to be addressed. That could be your problem too.
10-07-2016, 09:30 PM
#37
Re: Vibration Situation of Long Duration Causing Great Consternation
I would be leary of any such phone app. With a real vibration analyzer, you can greatly affect the reading simply by changing the sensor orientation or location. No way a phone is ever going to give you the accuracy you want after chasing this as long as you already have.
Driveline vibration is very different from wheel/tire speed and if you have a phone app. set to show the right range, you'll known instantly whether you have one, or the other, or both.
I can't find the info on the frequencies or ranges yet, or I'd have posted it already. But yes it works, and yes, you can narrow things down for basically free. My driveline vibration was a worn slip-yoke bushing and easy to find. Once replaced, that area of frequency was fine. The vibration of the tires was a different freq. and obvious (some inside weights had come loose.) Again, once fixed, it cleared up.
10-07-2016, 10:13 PM
#38
Senior Member
Re: Vibration Situation of Long Duration Causing Great Consternation
OP, whens the court date?
10-08-2016, 07:53 AM
#39
Re: Vibration Situation of Long Duration Causing Great Consternation
Tires, I don't know why you're so fascinated with the most disgusting part of this entire experience.
My greatest hope is there will be no court date. My greatest hope is, when presented with the "Demand For Repairs" letter my attorney has written, and shown the videos, photos, and written opinions from Centerforce, and two other transmission shops documenting the issues related to the work they have been paid to do, the shop will decide to do the right thing and make it right.
In The Art of War, Sun Tzu said "Pray for peace, but prepare for war." I may have to take this to court, but I will do it only as a last resort.
I have no desire to sit here and write about drama. This thread is about my vibration problem. If you have any thoughts, I'd love to hear them, but I have no further interest in discussing any tangental drama.
My greatest hope is there will be no court date. My greatest hope is, when presented with the "Demand For Repairs" letter my attorney has written, and shown the videos, photos, and written opinions from Centerforce, and two other transmission shops documenting the issues related to the work they have been paid to do, the shop will decide to do the right thing and make it right.
In The Art of War, Sun Tzu said "Pray for peace, but prepare for war." I may have to take this to court, but I will do it only as a last resort.
I have no desire to sit here and write about drama. This thread is about my vibration problem. If you have any thoughts, I'd love to hear them, but I have no further interest in discussing any tangental drama.
10-08-2016, 08:05 AM
#40
Senior Member
Re: Vibration Situation of Long Duration Causing Great Consternation
I know, and I feel for the situation guy. Hopen it all works out...you've seen my eds crook thread. An that mess AND the job still isn't right...
(neutral safety switch isn't hooked up/right to start in neutral)
Iv been in court with crooks before too.
(vids are on my youtube channel)
(neutral safety switch isn't hooked up/right to start in neutral)
Iv been in court with crooks before too.
(vids are on my youtube channel)
10-08-2016, 04:29 PM
#41
Re: Vibration Situation of Long Duration Causing Great Consternation
I'd definitely go over all exhaust mounts, hangers, and clamps to make sure its all tight.
You might as well replace the flywheel/ have it machined. that's a pretty strong possibility for the vibrations and with the rest of the trans being serviced already, why not finish the job. that would be my next move.
then I would change the tailshaft bushing, not sure about the T5 trannys but with the 700r4s you can have the tailshaft off in 20 minutes. I imagine a t5 isnt any harder. the bushing is super cheap so its worth the time.
Finally, I would start looking in that rear end, it may have been rebuilt and serviced but sometimes things just fail.
You might as well replace the flywheel/ have it machined. that's a pretty strong possibility for the vibrations and with the rest of the trans being serviced already, why not finish the job. that would be my next move.
then I would change the tailshaft bushing, not sure about the T5 trannys but with the 700r4s you can have the tailshaft off in 20 minutes. I imagine a t5 isnt any harder. the bushing is super cheap so its worth the time.
Finally, I would start looking in that rear end, it may have been rebuilt and serviced but sometimes things just fail.