Hey all, this noise just started up in my car today. When I'm making turns there seems to be a noise coming from the rear end. It doesn't sound like grinding, its fairly high pitched. When I got home I looked under the car to see if anything was rubbing and I saw this on the rear end cover...




Obviously my rear end is leaking. And I just took it for a drive to record the sound, but it wouldn't make it. Obviously I should get in there and change the fluid, make sure it seals again, or find a new cover to replace the old one.

Your thoughts on this? The sound only made an appearance when I was in a turn, such as making a right or left at an intersection. This sounds to me like the noise was coming from the differential.

Its a 1989 GTA, not sure what rear-end is on there but I cruise about 2,700rpm at 80mph which leads me to believe its the BW 3.27 rear end. According to the tech info on this site thats the only one listed for GTA's in 89 with the L98.

I recently had new rims and tires, balanced and mounted. When they mounted them I know they only used on jack one the rear of the car. They probably lifted from the axel correct? Could the way they lifted the rear end of the car have damaged the cover? I do know its bent by the lip of the cover.

 

Very good chance it is a axle bearing that is making your noise. Your rear is a 9 bolt, so it is most likely the axle bearings. I would remove the cover, clean it up and put new fliud in, While a part change both yoru axle bearing. The will need to be pressed off and on at a local shop. You will need to remove the tires, brakes etc. to be able to get at the 4 bolt on the inside of the backing plate to remove the axles. If you are turning right and it makes the noise, it is your drivers side bearing..if your turning left when it makes the noise it will be the passenger side bearing.

 

It did it on both sides, and it seems only when hot. When I took it for a ride to nail down the noise it no longer made the noise. Could this be because the axel was hot?

What is the average that this would cost at a local shop? I mean for them to do the bearings. Right now i have NO time to do this crap. I still have a crap load of things to do. The tranny mount is gone, and I need to do the rear u-joint while I'm at it.

I used to joke that I'd end up replacing the entire drive train someday but now i realize that its an entirely REAL possibility.

 

Well a U joint may have made some of that noise too. If your car has High miles then you should have it looked at to make sure your tackling the real problem. If it does it both ways, it can be a few things..the gear oil is low or old and needs a top up, or to be replaced. The bearings are shot, the U joint problem.. A shop will charge a good amount of cash for the axle bearings. It is most likely around a 4 - 6 hour job. so.. I would take it to a GOOD shop around you, one you can trust. Cause you can easily get ripped in a situation like this.. Good luck. Hope some of this helped?

 

Better than no help at all. I figure i can do the oil myself, but I don't have the time, tools, or skills nessecary to do the job myself. Changing the fluid wouldnt' be so bad, but doing the bearings would kill me. I'd probably screw them up good.

Guess its off to a shop to get a few estimates for the worst case scenario.

 

Replacing bearings on a 9 bolt axle is easy. You don't even have to remove the rear cover. Just remove the rear wheels and brakes, remove the 4 bolts on the axle retention flange and the axle will slide out. Then take it to a shop to have the new bearings installed. Should only be ~$30 to install the bearings.

Miles
Diff Solutions
www.9bolt.com

 

Now THAT is some good news! Care to recomend any reputable chains? Or should I go scout for some local shops. I don't know of any shops in the area.

 

Any automotive machine shop can do it and will likely have bearings in stock too. The 9 bolt uses tapered bearings, but straight will be more common. I would recommend using Timken bearings and races. The size needed is commonly known at a "set 9".

Miles

 

Can anyone recomend some good oils for the rear end?

 

Yes, I would like to know of the correct type of gear oil to use in my 9 bolt too. When they say "limited slip" that means posi-traction right? (I know, dumb question, just thought I would ask.) I just need to know what weight to use and how much my rear-end takes. It's got a 2.77 gear if that helps. Thanks. -89IRO

 

I don't have the 9 bolt (std. GM 10 bolt w/positraction). My 86 IROC started making noises in Sept. 02 while turning into a parking place at the mall. Since it is getting on in age and miles I took a (cheap) first step of draining the oil from the rear end and checking for metal particles. Since it looked pretty good I bolted the cover back up with a new gasket and sealer, squeezed in a tube of pos additive and refilled the rear end with the specified gear oil. No more noise in the last 7 months. Over time/miles that pos additive can loose effectiveness and the clutches in the rear (if your pos rear has clutches/springs) can start to stick and make noise when they have to release during a turn. Now that I've made that statement it'll probably fall apart on the way to work tomorrow. Good luck.

 

well....if your rear end is leaking......alot........and it's making noise......id think it would be self explanatory the first thing you'd want to look at...before it all goes boom

 

does that have posi? if so it may have run out of fluid and be shure to put the additive in there. outer bearings are not that hard, you will need a pull hammer and something to drive the new ones in, and new seals of course. but therem are still the innder bearings on the carrier. I donno about the 9 bolt but you either have 4 bolts on the outide that hold the axle in or there are c-clips on the inside of the spider gears you have to take out. good luck