Ok so I picked up a 3.42 rear disk brake rear end and I got all the stuff to service it including: gasket, Mobil 1 synthetic fluid, and GM posi additive.

I pull the cover and I didn't see the same type of posi I bought from SLP when they were selling the take out units. The one I bought from SLP a Torsen posi had gears inside. On this rear the posi inside has those horozontal springs inside and it looks just like my other rear with a Auburn posi.

So whats the deal, did GM uses both types of posi units in these LT1 cars? Now the thing that troubles me is that I read that your not supposed to use a synthetic fluid with auburn posi's. So should I try it with that fluid or change it out to non synthetic fluid?

Thanks

 

Yes they used both in the 4th gen cars. I always like using non synthetic oils in parts that work off friction.

 

Thats just great, I didn't realize they used both types of posi units.

So do I need to take that fluid out of there and buy some non synthetic fluid to replace it with or can these stock type Auburn units run with the synthetic?

 

If it is in there you will be fine.. I just like to use non syn. on rears and stuff. that is JMO on things.