My Motive 4.10 gears are a bit noisy on deceleration and its getting kind of annoying. They are perfectly quiet at constant speed and acceleration but once I let off the gas they make some noise. Someone at a local shop said to try a heavy duty gear oil like for trucks or something. Not sure exactly what grade he said but will this infact quiet the gears down a little by using a different type of fluid? Right now I am running the Mobile 1 75w90 synthetic fluid and the GM additive.
Thanks

 

Yes...

I used to run 85w-140 when I had my 4.10's to keep them quiet.

-Dave C. '97 Z28

PS: Make sure you still use the limited slip additive.

 

Using the wrong additive can be either terrible for the gears or hard on your ears or both...friend of mine went to get a fluid change and they put in the wrong fluid and he brought it over cause it was making a terrible noise...sure enough wrong fluid...no damage done though...

 

IrocManiac,
I am referring to the actual gear oil itself NOT the additive as no matter what fluid I use I would still use the GM limited slip additive. Maybe im misunderstanding you but any type of gear fluid should work just make sure in our cars we use the GM additive. Is this what your saying or were you talking about the gear fluid itself?