Tom Johnson

I put in Amsoil synthetic gear oil without the modifier and I got a medium pitched howling noise when i made a right or left turn. I put some GM modifier in the rear end and it stopped. Has anybody here ran synthetic gear oil for a few years. Since Amsoil claims you can run there gear oil without a modifier and is false. I am wondering about all there other claims. One forum member warned me not to use synthetic oil in the rear end because it ruined his. But all the other posts were positive. I'm thinking on pullin the synthetic out and replacing it with GM oil and modifier.

Garson

I would make sure that the oil is good for the use in limited slip diff.
I know that some are not......

garson

jerryp58

I appreciate the post since I am toying with the idea of doing this myself (I watched the last post on this too and I thought Amsoil was highly praised).

What was the condition of the oil you got out of there?

73 LS-4

I ran synthetic gear oil for a few years, not in the vette since I haven't had it a year but it's in there too, but I ran it in my ranger for 3-4 years without a problem, both cars did have the modifiers in them however.

:cheers:
Pat Kunz

nastee383

I have used Royal Purple for about 2 years now without additives and without noises or problems. And my car ocassionally does "hard time" at the track.

69er

I had my rear rebuilt last year.
The shop Level 10 has been featured in many performance magazines.
They also did a performance rebuild on my trans.
New GM 3.55's and new posi unit were added to the rear.
Had chatter after long straight highway driving with GM oil and additive.
Was told by my rebuilder and verified by "GM parts Guru"Joe Lucia that the posi clutch packs are different than the originals and many rear rebuilds have a chatter problem after long straight runs when making the first few left or right turns.Even after 5-6 hundred miles.
A friend reminded me which I then remembered about a rear posi problem he had on a new chevy wagon he bought in the late eighties with posi chatter problem.
The car was brought back to Chevy service a number of times but the problem was never fixed.
Another friend at the time was a Amsoil distributor.He suggested trying Amsoil rear oil.He did and problem was solved.
I decided to try Amsoil with GM additive and the chatter problem immediately stopped and I haven't had a problem since.
I was so happy with Amsoil that I now use Amsoil synthetic 10w40 in my engine.
Just my experience with Amsoil.





[Modified by 69er, 4:58 AM 12/21/2001]

mountainmotor

My reply has nothing to do with the positration ability
or lack of but I have always struggled with the idea of putting that thin fluid in a high mile differential with a certain amount of initial clearance wear.Certainly it has good film strength but the viscosity is what worried me into never using it at all

Tom Johnson

The rear end was just rebuilt. The oil only had about 2,000 miles on it.