Rearend Noise

**oharam** · 09-25-2011, 09:58 PM

I need some help, and input on this please. Out of no where, my rear started making a "clunking" sound when I would turn the car, and has gotten ALOT worse. I put it on a lift at work tonight, and when I spun the passenger rear tire, the drivers side did not spin until the passenger side did 1 full spin, then the drivers side would spin same direction. Is this going to be a major rebuild, or is it going to be something simple? I dont have the funds to put a stronger rear in it yet, so I am tight for cash and need the least expensive route.

Thanks for the help!

Mike

**Smittro** · 09-25-2011, 10:45 PM

The 10-bolt is a weak unit, you'll need to pop the diff cover off and see what's going on inside before cost of repairs can be determined..

Sounds like the differential crapped out, could be a ring and pinion issue as well..

Open it up and post some pics if you can.. That way we can help you more..

**oharam** · 09-26-2011, 03:12 AM

Maybe this will help as well. It is only making the noise when I make left or right hand turns, and I cant hear anything going forward, or in reverse, and cant feel anykind of vibration (yet).

**pajeff02** · 09-26-2011, 03:27 AM

Like Smittro suggested, get the back of the car in the air and check things out. Pulling the cover is real simple and for reassembly you only need a new gasket (or RTV) and some gear oil and posi additive.

**Knight** · 09-26-2011, 05:36 AM

Agree with Jeff and Smittro, it's best to pop the cover off and see whag's going on. It does sound like a carrier issue.

**oharam** · 09-26-2011, 04:07 PM

I havent popped the cover off, but jacked up the back end and the wheels spin freely, and cant find any kind of play in the wheels (up, down, left, right, in or out). I did find the fluid is shot, and is pretty nasty. Going to takee it to work tomorrow night and pop cover off and take a look see, and post some pictures.

**My00Z28** · 09-26-2011, 04:26 PM

Originally Posted by pajeff02

Like Smittro suggested, get the back of the car in the air and check things out. Pulling the cover is real simple and for reassembly you only need a new gasket (or RTV) and some gear oil and posi additive.

dont our cars have tru-trac's in them? so a posi additive wouldnt be necessary. Correct?

**Knight** · 09-26-2011, 04:41 PM

Originally Posted by My00Z28

dont our cars have tru-trac's in them? so a posi additive wouldnt be necessary. Correct?

No, they do not come with the Tru-Trac differential from the factory.

**My00Z28** · 09-26-2011, 04:49 PM

Really? lol cause when i did my diff fluid i swear mine is a Tru-Trac? i guess mine isnt original?

**pajeff02** · 09-26-2011, 05:45 PM

In either 2000 or 2001, I believe they changed over to a Torsen gear type posi. Although there are no clutches or friction materials in these type of differentials, the manufacturer recommends the use of a positraction additive. There were cases in which the differentials were noisy and the remedy was to run the additive. I have posted the link on this at least two other times -- just takes me a minute to find it.

**pajeff02** · 09-26-2011, 05:46 PM

Here is the quote from Torsen's website: GM issued a technical bulletin adding modifier to the rear axle oil. This was done to quiet what we call a "Rusty Screw" noise that we heard in a very small percentage of vehicles. This does not happen in all cases, however to address owner's concerns we asked that the modifier be used in all instances to insure that the driver would not get this noise. When replacing the fluid it is at the owner's discretion whether or not to add the modifier. Elimination of the modifier does not affect durability of the differential.

**My00Z28** · 09-26-2011, 06:49 PM

ah ya the torsen is what mines got sorry!!!! back to OPs thread

Thanks!

**oharam** · 09-27-2011, 08:18 AM

Now, let me throw this monkey wrench into it. I drove it this morning, and was still doing it, BUT this time I kept it out of gear while turning and there was NO noise, or clatter, or banging. The only time it does this, is while in gear and turning.

**TLS_Addict** · 09-27-2011, 08:34 AM

Originally Posted by pajeff02

Like Smittro suggested, get the back of the car in the air and check things out. Pulling the cover is real simple and for reassembly you only need a new gasket (or RTV) and some gear oil and posi additive.

Remember to snip the end of the gear oil jug........

Originally Posted by oharam

Now, let me throw this monkey wrench into it. I drove it this morning, and was still doing it, BUT this time I kept it out of gear while turning and there was NO noise, or clatter, or banging. The only time it does this, is while in gear and turning.

In gear are you under load (on the gas) or in gear but coasting and the throttle is closed or closing?

Are you sure its not a tranny "clunk" instead of the rear end? Any tranny leak out the tail shaft?

**Knight** · 09-27-2011, 09:07 AM

Depending on the answer to Dan's questions, it still sounds like it could be the differential to me. Under a load, it is having a problem transfering power to the wheels. I'd open up the cover and inspect it.

**oharam** · 09-27-2011, 09:23 AM

TLS: does it while in gear, both coasting and using throttle. I did look again at the tailshaft of the transmission, and cant see anything noticable leaking from it.

Now, I did just put it in the air again, and this time I have notice some endplay on both rear wheels (going in and out), but nothing by trying to move the wheel left or right or up and down, just in and out.

**oharam** · 09-29-2011, 10:05 AM

Well, had it pulled apart this morning, and the spider gears in the carrier are shot. Ring and Pinion are in good shape, and both axles are in good shape. Now I just need to find a replacement for cheap to get it back on the road.

**Knight** · 09-29-2011, 12:39 PM

I figured that was it. You should be able to find a carrier pretty easy. Shoot Spaz a PM, he has my old one. Still works I think. He broke an axle. See if he'll let it go. It's a Tru-Trac too.

**oharam** · 10-03-2011, 12:19 PM

So, I thought my problems were done. Got a new carrier and gears (Eaton Posi), which came out of a GM 10 bolt, my ring gear bolted right up,and axles both fit. My mechanic goes to install everything, and ordered a shim kit for it, and now he is saying the carrier is to big for the housing and isnt going to work.....FML

**oharam** · 10-03-2011, 08:10 PM

Glad my mechanic looked into what rearend i had. He based his info on "what" came in it, and not "what" was in it. At some point the rear was swapped out with a 2 series carrier and a 2.73 gearing. Exchanged the 3 series carrier for the 2 series carrier and now all should work. Time will tell tomorrow!