Rear chatter while turning

**slade8200** · 09-25-2014, 09:21 AM

It doesn't sound like it's coming from the rear end. The sound sounds like it's coming from the outside of the car, like a rear wheel bearing maybe. I saw the sticky about these, but no one described the sound the way I hear it. It only happens while making hard turns going above 30mph, and more pronounced on the left side.

***SMWS6TA*** · 09-25-2014, 10:24 AM

sounds more like the slip posi is going out. When's the last time you did a fluid change on the rear? Did you add the additive?

**slade8200** · 09-25-2014, 01:00 PM

I've never changed the fluid. It doesn't appear anywhere in the service manual. I only have 36k miles on it.

***SMWS6TA*** · 09-25-2014, 01:15 PM

36k total miles ever or you've only put on 36k since you've gotten it?

Also do you see any seepage on the center chunk or around the wheel hubs?

**98TransAmWs-6** · 09-25-2014, 01:23 PM

Sounds like what happened on mine. I changed the fluid with one with the limited slip additive and the sound went away.

***SMWS6TA*** · 09-25-2014, 01:42 PM

That's what I'm leaning towards....

**35th-ANV-SS** · 09-25-2014, 01:50 PM

Originally Posted by slade8200

I've never changed the fluid. It doesn't appear anywhere in the service manual. I only have 36k miles on it.

This is from the service manual -

Rear Axle - Standard Differential
Use SAE 75W-90 Synthetic Axle Lubricant (GM Part #12378261 or equivalent meeting GM Specification 9986115).

Change every 30,000 miles

Rear Axle - Limited-Slip Differential
Use SAE 75W-90 Synthetic Axle Lubricant (GM Part #12378261 or equivalent meeting GM Specification 9986115). With a complete drain and refill add 4 ounces of Limited-Slip Axle Lubricant Additive (GM Part #1052358 or equivalent). Even though the 2000 model year and later F-body limited-slip differentials are a gear type Torsen unit, the use of a limited-slip additive is still recommended.

Change every 30,000 miles

**slade8200** · 09-26-2014, 04:34 AM

36k total.

No seepage at the ends of the axles.

Where is that part in the service manual? On page 0-34 I see nothing about that at that 30k mile mark. 30k seems kind of early for axle fluid anyways doesn't it?

**98TransAmWs-6** · 09-26-2014, 05:18 AM

Originally Posted by slade8200

36k total.

No seepage at the ends of the axles.

Where is that part in the service manual? On page 0-34 I see nothing about that at that 30k mile mark. 30k seems kind of early for axle fluid anyways doesn't it?

I would still change it if it has never been changed due to the age of the car. It is cheap and easy to do. It will likely fix the problem but if it doesn't for some reason you haven't spent too much money either.

**35th-ANV-SS** · 09-26-2014, 06:19 AM

Your fluid is 13 years old. That's pretty excessive. It does break down over time. You probably have sludge for gear oil.

I wrote the sticky for general routine maintenance, which is where I copied and pasted the above from. It all came from the service manual I believe. I'll have to go look next time I'm out in the garage.