Need some advice. Just bought a Moser 12 Bolt limited slip. Instructions say to use a mineral base 80-90 gear oil and add 4oz of LSD additive. The parts people and friends say to us Redline synthetic. Instructions say not designed for synthetic but my friends say they run it and it made the rear end quiet. Can anyone out there share their experience or give advice.

good question....welcome to team camaro greg

Welcome to TC Greg!

Lots of good info here for the searching. Here's one good thread:

http://www.camaros.net/forums/showthread.php?t=98794&highlight=synthetic

I have used Amsoil synthetic oil in over 100 of these with no problems.

:) I still have a few bottles of 'whale oil' additive which GM used to sell as positraction / limited slip additives. I suspect it's still 'good'.. it's only been 30 yrs or so :)

Lucas brand 80w90 has the posi additive already in it. I called Eaton and asked about what type of oil to put in it and they said that the lucas would be fine and not to use a synthetic because it would be "too slippery" for the clutches in the posi and cause excessive chatter in turns. The rear in my car has been quiet and trouble free since I redone it about 3 years ago.

Thanks for the info and additional threads. They gave me a lot of information. I am rebuilding a 69 and I can see that this forum is going to really be helpful. Thanks.

I have a Moser 12 bolt in my 67. I broke it in with Lucas gear oil. I later drained it and put BG synthetic oil in it. I haven't had any issues with using the synthetic oil. If the BG oil was not given to me by a BG salesman, I would have stuck with the Lucas though.

When I got my new Eaton for my rear I used std dino oil and additive for break-in for the first 1000 miles "like you do an engine" then switched to the Red-line synthetic for less friction loss.