I was told that since I was replacing the originals (yes I know, way overdue) that the replacements have C-clips and It may cause a vibration. He told me that the factory didn't use the clips and instead, pumped a plastic type stuff around the bearing cups, so no clips were used.

This sound right to you??

Anyways, now I have a vibration around 55 MPH that seems to shake the shifter real bad, but I can feel it throughout the car also. I also replaced the tranny mount too. Would that affect it?
Should I just have the driveshaft balanced now??

Thanks in advance for any replies.....

 

That is exactly right; the original U-joints had a groove around them, and the yoke has a corresponding groove, and the factory injected molten plastic on there rather than using clips. Replacement ones all have clips.

It's difficult to get the OE ones out without bending the yoke, unless you use heat. That may be what happened. You might wnt to take the car to a drive shaft shop and tell them to "fix the vibration", not "balance the shaft" or something specific like that, see what they tell you.

 

Thx RB!!!

I'm taking it back to the shop that installed the UV joints on Monday. Told them my problem, and they said it would need to be balanced checked and/or re-balanced, and that would cost 48 bucks. If they have to straighten it, it's like an additional 10 bucks. I dunno...it's the same shop that did all the machine work on my engine, so they know what they're doing.

I reeaaallyy hope it's not the trans causing this.

 

I've run into a similar problem. Got my aluminum shaft and had the u-joint replaced with a spicer unit. I also had them balance the shaft as well. They confirmed that the shaft is not bent and that the yoke is good.

Now when travelling at highway speeds the vibration starts at 65-70mhp or so mph and gets progressively worse. The shifter shakes extremelly bad beyond this speed.

If I put the trans in neutral (5 speed) the vibration is still really bad until it slows to less than 70mph (120kph or so). The bearings in the 9bolt rear were just replaced in October 2002. The tranny has been professionaly rebuilt and I installed a new bushing in the tailshaft as well.

Oh, I have a prothane poly trans mount from spohn as well as torque arm mount..

I need opinions. I have a couple of guesses and am open to more...

1. Improper balance job
2. Bent outputshaft in tranny/tranny problem
3. Wheel bearings (got this in the archives)
4. Posi cone clutch-unit problem (also got this in the archives)

Help.

Thanks

 

read my response in this thread
https://www.thirdgen.org/techbb2/sho...hreadid=183935

Possible it is not fixable with out new ends on driveshaft!

 

I don't believe that at all.
Like the last post in your link, I'm thinking that they just aren't balancing it for high enough speed. Like that guy, I have a 9bolt 3.45 Which means my shaft spins faster than most others.

I think we're on to something. I'm going to call them up tomorrow and inquire about what method they used to balance it, what ratios they used, and how fast.

 

WoW!!!

I wish I would have looked at this earlier! I sent mine in today, to get balanced.

Knowing that there's a 50/50 chance on this thing not vibrating is not good odds IMO.

When I picked it up from them after the UV joints were installed, the guy said the same thing to me about the plastic injection in the cups, and the possibility for vibration. At least he was honest
and gave me a "heads-up".

He said it would possibly need to be balanced, so here I am....

But like I said earlier, they seem to know thier s**t, although they're not cheap.

 

Well, got my drive shaft back today. The guy that did the work said it was 60 grams out of balance - which seems like a lot to me!

He also said it was bent .004, so when I get a minute of free time, guess I'll install it and give it a try. (fingers crossed)

 

Give it a shot and let us know how you did...

 

Well, I installed and tested it today, and although it seems to be much better, the vibration is not totally gone.

Now between having UV joints pressed out and having this stupid driveshaft balanced, I've spent nearly 100 bucks - and it still ain't right!!

I almost feel like saying the h*ll with it all. and getting another one at the junkyard with the original UV joints still in it and just running that.

I'm trying to figure out if that's actually the problem in the 1st place because I installed my G force trans, replaced the UV joints and installed a new trans mount all at the same time. My intentions were to tighten everything up since I was under the car anyways. Oh, I also replaced the rear driveshaft yoke seal.

I don't think a trans would cause it, or else it would vibrate at any speed right?? I only feel the vibration now between 65-70 MPH. I mainly feel it in the shifter, not the steering wheel. It's smooth otherwise. All tires balanced too. Even my speedo is working again after installing this trans!!

It's kinda hard to report on how this new tranny actually performs with this vibration problem going on.

Any advice you guys may have on this would be greatly appreciated, because I'm at wit's end!!

 

Try balancing it yourself....

Put 2 hose clamps at one end, right together, turned exactly 180° from each other; since it's affecting the shifter, I'd start at the front. Drive the car; it shouldn't change much if at all. Move one of them. See if it gets better or worse. etc. etc. etc. The farther from exactly 180° apart (the closer together) they are, the greater the "balance weight" you're applying; the center between them is the "location" of the "virtual balance weight".

 

Thanks once again RB!!

Yet another use for hose clamps! Seems a little time consuming though...but I'll give it a shot. What do I have to lose??

Anyone know of anything else that could cause this??

 

I do believe it! IMHO

Well The guy that does the drive shafts for me does them from all over the world! He said that some times it is necessary to replace the ends of the shaft because they are pressed in place and with the plastice injection method it over comes the short commings of the shaft ends being out of tolerance. However, when the Ujoints have to be replaced the whole alignment method goes out the window, unless, you had the Jig/macine that GM uses when making the drive shafts. Basically all GM shafts are a piece of **** when it comes time to repace U joints.

He also said he would not recommend putting money into a stock GM shaft if the UJoints give you problems. In the long run a decient new steel shaft would probably be cheaper then trying to fix a screwed stock one.

 

Rb, should I put a small weight under the hose clamp (I assume you're talking about the regular runofthemill hose clamps commonly used for duct work, coolant hoses, etc)...or is the weight of the screw mechanism part of it enough to set things off a little...

 

Well just for an update on this post, I again removed the drive shaft and it's back in the shop.

What's worse is the guy at the shop is now saying that it checked out OK before, so my problem must be somewhere else!

I told him I had no problem at all before I had these U joints pressed in, and I bet if I got another drive shaft from another car, it would work fine. He kinda grumbled a little and said he'd check it again....

So here I am....ROUND THREE.

If this doesn't work, I intend to get my 60 bucks back for the "balance" and try what RB says above... and if that doesn't work, I'll get one from the junkyard w/original U joints in it and start all over again.

I thought I was doing a good thing by replacing the U joints, but now I wish I'd never touched them!!

No matter what, there's no up-side to this. Anyone know of something else I should check??????

 

Keep going dude. I'm in the same boat

 

Another update.... I took it back to the shop...see post above.

They said they balanced it this time even better than what the specs call for. Seems to have solved it!!!
I've had it to 80, and I don't feel anything in the shifter anymore!

And except for the slightly noisier gears, I'm lovin this tranny.

How about 1800 RPM's at 65 MPH in fifth?? That's with 3.73:1 rear gears!!! That's the same I would've gotten with a six speed, (I think)!!

It has a .56 5th in it.

And the first 4 gears are still nice and low....but it sounds weird when going from forth into fifth if you don't wind out forth quite a bit 1st....

Oh and BTW, I'd recommend the Pro-5.0.....makes a world of difference! :hail:

 

Congrats! all of us with this type of vibration issues can learn from your persistance! Enjoy the vibration free ride!