stas

Hi guys and gals, my car ('01 Z06) recently developed a kind of grinding noise from the rear end. It sounds a little like braking with a warped rotor (on, off, on, off).. The noise occurs when I'm making sharp turns at slow speeds. Is there a way to check if something is wrong with the limited slip? I have changed my rear end fluid to AMSOIL Severe gear fluid this year which already has friction modifier in it. I'm ruling out the fluid because there was no noise right after I changed it, even after track sessions. Any suggestions as to what else it can be?

Thanks in advance, Stas.

Sinister-one

But did you buy and add "Slip Lock Differential Additive" which is sold separately ?

stas

Hi, I read in another post that none is required on the C5.. see below.

"The AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 comes with friction modifier already in it and extra is not normally needed in C5s to prevent diff chatter. I use this fluid without extra additive in both my 02 C5 Z06 track car and in my 06 Cadillac CTS-V and neither diff chatters. "

Sinister-one

The key phrase there is "not mormally".... In speaking with AMSOIL and being a dealer, I can tell you that you DO need the additive.

Point & Shoot

First check your fluid level. If that's OK, then I recommend changing the fluid to the new GM formula which already has the friction modifier and see if that helps.

I always start with the easy, simple stuff and work from there. Good luck.

Cybermind

When I changed my diff fluid I was told that no matter what gear oil I choose, I should still add the GM additive. That is exactly what I did and no noise whatsoever.

stas

Thanks for the replies guys. I'll give that a shot when I change the fluid for spring (car not being driven now). The thing that I find surprising is that the noise did not start right after the fluid change. Should the noise go right away if it is indeed the lack of limited slip additive?

Stas.

Sinister-one

YES.

Carlos Arredondo

the same thing is happening to me. Had oil changed, no noise. 1000 miles later, noise at low spesd sharp turns. Added another bottel of additive, noise gone. 500 miles miles later, noise came back

Ikester

...I swapped to Amsoil severe 3 years ago without additive..no issues...was advised by Amsoil rep to add it only if there was noise on turns.

still quiet wit 4.10s guess some diffs are different then others