So last night my Camaro IROC Z began howling when I reach 55 MPH and around 1800 RPM. I am not sure of where the howling is coming from. But I will post the sounds of it below. It started after I was already driving for 45 minutes. I had already driven around 80-90 on a freeway, slowed down and drove 70 on a two lane highway. It began when I got off the highway onto a backroad. I came to a complete stop, made the right on to the backroad and when I reached 55 the car began howling. Temp normal, engine RPM normal and oil pressure normal. Later when I got close to home my Fuse Gauge blew and now keeps on blowing. Are the two problems connected?

In the first clip the howling starts around 20 seconds.

 

Eliminate possibilities. Try driving the same speed in different gears, coast in neutral, hold the engine at the same RPM and put the car in neutral, determine if it's RPM, trans, or speed dependent. That'll give you a better idea where to look.

 

I tried driving in both OD and D, the car makes the same noise starting at 55 MPH, it's loudest at 55 and quiets down a bit at 70. I can't tell you the RPMs until I figure out what is blowing that gauge fuse.

When I let the car coast and slow down it makes the noise until it drops below 50 and then it disappears completely. Any idea what it could be?

 

Does the noise continue while traveling at speed with the engine idling in neutral? Is the noise localized? Could be anything from the heater fan bearing failing, to a dry speedometer cable, noisy speedometer, an accessory bearing failure (alt, waterpump, smog pump), rear end, transmission, etc. Gotta narrow it down.

 

Drivetrain related, my guess is the driveshaft at that specific speed is resonating (out of balance).
A hurt trans, or rear end would make noise at any speed any typically the noise gets worse, stays steady, the faster you go.

The stock driveshaft is OK for "normal" driving on a OEM stock car, An original 34 year old one has worn u-joints and if you have beat on it it's on it's way out. (because no one drive 3rd gens hard...) if you have never service the driveshaft that is a good place to start and you can tell if the u-joints are OEM since there will not be any C clips holding them in place.. GM injected plastic retainers which you have to burn out with a propane torch to melt the plastic. once you do that you can install new u-joints.
If you want to keep the OEM driveshaft find a driveshaft shop to test and balance it for you first before installing new u-joints.

Otherwise, if you are making more power than stock, throw that junk out and get a new aluminum driveshaft. Inland Empire makes them for 3rd gens that comes with new Spicer u-joints. https://www.summitracing.com/parts/i...olet/year/1986

I had a similar problem with mine when I had the 383. even with new u-joints on the oem shaft after a few season of hard driving I developed this terrible vibration at 40-50 mph the dash pad would shake. I replaced the stock driveshaft with the Inland Empire part and it was better than new.

The vibration could have shook your wiring and chafed the insulation so you may have a short to ground on the tach wiring... check the wiring at the coil.

 

It could very likely be drive train related and I'm going to lean that way for now. I did have my 700R4 fully rebuilt and my rear end serviced 3 years ago. I have no idea if they replaced my driveshaft or not.

I want to fix this ASAP but more than likely won't be able to get any parts until Monday at the soonest (none of the Auto parts stores carry parts for our cars in my area. Not even O'Reilly's. Even thing has to be ordered and it takes 2 to 5 to get there).

Is it safe to drive long distances for now? I have to make an 80 mile round trip on Sunday. I'm now worried if the driveshaft will fail.

 

I went out again and bumped my 700R4 into neutral (I'm not sure If I am suppose to do that), the noise continued until it dropped below 50 and went away. I came to a stop, shifted back into OD and when I reached 55 it came back as usual. I don't think its the rear end or transmission as both have been rebuilt in less than 3 years. But the other parts you mentioned could be.

 

Eliminate the obvious:
Did you check the trans fluid? is it correct level on dipstick, does it look/smell burnt or still pink and smell like normal trans fluid?
Did you check the rearend? is the rear cover full of oil, is there oil all over the rear brakes, if OK is the fluid level low?
Does the driveshaft and u-joints look like 34 years parts that have never been touched? with the car in park how much free-play does the driveshaft have when you rotate it by hand ? do the u joints it make funny sounds when you check the free play?

Engine noises:
Worn out parts will make constant unusual noise(s) that and get worse at speed (alternator, water pump fan, v-belts or serpentine belt)
At idle a normal stock engine without worn out parts will be pretty darn quiet is should sound like smooth mechanical music with an exhaust note. Hard to explain this over a keypad but any parts at fault will simply sound out of place.
A high performance engine will just be louder because of the exhaust system (or lack of ) maybe it has solid lifters too but a trained ear can pick out any odd sounding noises.

Interior noises:
Bad speedometer gage or cable? is the movement of the needle smooth or erratic? It should be smooth, if not something is amiss.

 

I'm don't think it's anything is wrong under the hood. The idle is smooth, I know alternator was replaced recently as were the belts. I don't have a water pump fan, it's electric. The only thing is a vacuum leak somewhere but that's a different noise.

When I rev the engine in park no strange noise, when I hold WOT in park same, it's normal.

I backed up my car on ramps (I need new jack stands, lost them in a move). Rear end looks fine, no signs of leaking fluid anywhere, brakes are clean. The driftshaft and u-joint both do look old. The u-joint looks rusty as hell, no fluid or oil anywhere though. Brakes, gas tank, exhaust, pipes, etc are all clean. I couldn't really move the driftshaft by hand but I didn't notice any play.

I don't think it's an interior noise, it sounds like its coming from outside of the car. I can't pinpoint where though. It's just outside the car. As far as I know, Speedo is normal. It reads fine and needle is smooth.

 

the factory u-joints are non-serviceable once you melt the plastic you have to install new ones with c-clips to retain the bearing caps. I would remove and replace those at the very least.

 

None of the auto parts stores near me have an U-Joints in stock. Is it safe to drive in the mean time or is my car a ticking time bomb?

 

Dude, I can't make that call for you but I know what I would do.

A rental car is way better than breaking down road kill style like those 2 lovable idiots who have chase crew to bail them out.

 

if you have jack stands you can get the car up with wheels off the ground. put the trans in neutral and try to turn the driveshaft by hand... it should turn with some effort, if it feels sloppy or it's binding u joints are bad and will get worse. You you can try turning the RH wheel too to check the rear end . the wheels should turn smoothly I would not rule out worn ring/pinion gear or bearings. Listen for any funny sounds.. You might as well check the front wheel bearings for play and binding too.

2 other things to check are the transmission mount and the torque arm mounts; if they are worn out at high speed the trans yoke / pinion angle could be out of spec and binding the u-joints, making the howling noise.
Don't assume they replaced any mounts when your trans and rear were serviced.

 

A buddy of mine use to be a tech and has jack stands. I'm going to see if he is around Monday to see if he can take a look at it. I know for a fact my transmission mounts were replaced. I remember when they were bad my car vibrated a bit and use to feel like someone was smacking the bottom of the car when it was put in R or OD. It doesn't do that currently. They were replaced 3 years ago.

I will check the wheel bearings as well. The last time I had a full brake job with new rotors was 5 years ago and not a ton of miles have been put on my car (it wasn't my daily driver until a few years ago). The rotors are ACDelco but the bearings were some other brand and likely made in China. They could be worn.

 

Update: My buddy took a look at it and sees it's definitely rear end noise. He says it does it sound super bad but you never really know until you pop the cover off. Fingers crossed. I'll keep everyone updated.

 

So apparently, my rear end is a 9-Bolt 3.70 rear end. I know GM made a handful of 9-bolt GM rear ends but I thought this only came on the L69 cars with the 5-speed. My is an LB9 car (F Vin code) with a 700R4. I'm assuming somebody swapped this on here a long time ago.

 

Ah yes the Australian built Borg Warner 9 bolt.

It has a 7.75" ring gear (10 bolt is 7.50") this was the strongest factory installed rear end on some of the "high performance" third gens from 85-91 but won't last long in a 11 sec car.

Aftermarket gears were not available 35 years ago, but you should be able to get aftermarket bearings. If the ring and pinion are worn you will have source New Old Stock or just upgrade to a 12 bolt, 9" or Dana 44.

If you can find choose the Dana 44 it has a 8.5" ring gear and is plenty strong for a car that is street driven and not raced at the track every weekend. If you want a bullet proof rear and plan to hammer on the car at the track the 12 bolt and 9" are better choices.

 

For now I just want the car driving again. It's rarely raced or hooned any more. My buddy is going to look later to see what's really wrong with the rear end. I did some googling is this Ring and Pinion ok? https://www.jegs.com/i/Motive-Gear/683/GM9-370/10002/-1 It seems the same as stock.

In the future I'll probably upgrade to a 9" but for now I just want this car back in the road. If that ring and pinion works, I'm ok for now.

 

Well it looks like the aftermarket saw a need to make ring and pinion set for the 9 bolt, that is great news for you.

Is it OK ? again I am not the car owner. If your 9 bolt rear already has a 3.70 ring and pinion.. then it's an easy remove and replace process, but you are missing the point.
Someone needs to take apart & inspect the rear diff to determine what has failed/worn out. if teeth are missing on the ring and pinion well that is obvious but there are bearings, axles, and posi-carrier to check too. not to mention tolerances.

make sure you can get all the hard parts to do a complete rebuild

 

 

Well I learned today that the Borg Warner Australian 9 bolt has bolt-in axles and not the useless c-clips, so that is big plus compared to the stock 10-bolt.

If you can get the parts to rebuild it I would since your intention is not to hammer on it at the track.