BGMZ28

I want to change my diff fluid I think it is the original 12yr old fluid, granted only 50K on it but I would like to upgrade to synthetic. I have done a search and have found mixed results about running synthetic fluid, so I am undecided on what route to take? I know you need to add the GM friction adifer to the diff with the fluid and from what I gathered redline seems the way to go. I just want to get another opinion before I go ahead and change the fluid. I currently have a quite non leaking rear end and would like to keep it that way and if synthetic is going to mess that up I’ll stick with the regular stuff. Thanks

QwkTrip

iTrader: (23)

Royal Purple makes a good product, too.

What year car do you have? You don't need a friction modifier with the Zexel Torsen. It's harmless if you want to add it anyway.

01ssreda4

iTrader: (96)

What year is your car? 99-02 usually don't need the additive bc they have a torsen posi thats all gear driven. Syn fluid has the additive already in it.

Tobias05

iTrader: (1)

changed to royal purple a few months ago. used a new gasket, and tq'd the cover in a star pattern, with a tq wrench, to the specified ft-lbs. no leaks.

BGMZ28

I got a 98 isn't that the Auburn which requires the adifier? Or am I good since your saying synthetic already has it in it? Also What was the Trq for the diff cover? Thanks again

QwkTrip

iTrader: (23)

Auburn does require a friction modifier. Some oils come with the modifier and it should say on the bottle.

killagt

iTrader: (3)

if u got 98 with auburn, then STAY AWAY FROM SYNTHETIC , using valvoline 80w90 with GM/Ford friction modify ( I find out that ford stuff is better and its like 5 dollar cheaper then gm stuff ). Change every 2 year or 30k miles.

Right now im using Lucas 80w90 that already have friction mod in it, add ford friction, cool and quiet ^^.

Tobias05

iTrader: (1)

25 ft-lbs.

BGMZ28

Why do you say no on synthetic with the auburn? Thanks for the trq specs.

Tobias05

iTrader: (1)

IIRC it's because it has clutches as opposed to the Torsen which is "just" gears.

My eaton posi 19599-010 in my 87 takes dino oil as well. It too is a clutch style LSD.

http://www.summitracing.com/parts/ETN-19599-010/

I've run that fancy lakewood stuff, and basic valvoline.

http://www.summitracing.com/parts/LAK-32970/

BGMZ28

Changed out the fluid yesterday with valvoline and the ford stuff it was like 5 bucks at the dealer. So far nice and quiet thanks again guys.

O2Form

Auburn uses a cone clutch that isn't synthetic friendly. I installed a brand new Auburn and tried using Mobil 1 synthetic gear oil, It wasn't good. The cone clutches didn't like it and I ended with a rear full of metal from the clutches in 2k miles. I went back to a Torsen carrier, car handles so much better.

nascarnate326

iTrader: (1)

I use the synthetic valvoline in my 96.

Hatchetman337

iTrader: (3)

So to resurrect this thread for a question, I have an 01 WS6. That would be ok to use synthetic in, right? Does anyone recommend a good place to buy the good stuff to save some cash?

Darth Cypher

I have an '01 Z28 and am thinking about changing my diff fluid this weekend. I still have the stock 10 bolt and won't upgrade my rear for years (other things to do first). What fluid and should I use a gasket or RTV?

EDIT: Let me rephrase - I know what fluid to use, I just don't know if I need any additive or not.