Fluid recomendations

[LS1 2001 Z28]

Ok i read the FAQ's however i could not see a recomended fluid change for the rear end and manual tranny. How often does everyone change these and what fluids fo you recomend?

[Blacker]

If you have the Auburn Differential, use 85W-90 and 2oz of GM Anti-Slip Additive. If you have the Torsen Differential, use Redline 75W-90. I started using the Redline Fluid and the rearend has gotten quiter over the GM Fluid. You can get the Redline 75W-90 for $7 a quart and it is well worth it.

[killer01ws6]

I changed my tranny at 21k and will do it at 15k intervals from here on out. I put in normal ATF.

The rear should be changed the first time at like 1500 miles or so
then every 15k or so as well.

I ran a synth 140w- 90 with the gm additive.

Do not run synth if you have a auburn rear.

I know you do not, but for others reading this;)

[Blacker]

It appears you have a 2001 Z28 and they came with the Torsen Differential. You can use Synthetic Fluid and the anti-slip additve is not necessary since this differential doesn't have clutch packs. SLP has an option for a HD Auburn for the SS.

[LS1 2001 Z28]

Cool thanks for the reply i will do those both when it gets warmer out. Great to see all the same mods here helping. :)

[jumpcable]

What about the 2000s, they came with Torsens didn't they? Just wondering because I put Mobile One Synth in my rear-end when I last changed the fluid.

One more question, why exactly does one require synth and the other not?

Thanks - Patrick :D

[killer01ws6]

you don't have to put synth in the rear of the torsen, but the reason you don't want it in the auburn is the clutch packs will slip and chatter hurting you instead of helping.

[jumpcable]

So I guess I'm good...I couldn't remember which one I had. :D

[jmd]

Originally posted by jumpcable
What about the 2000s, they came with Torsens didn't they? Just wondering because I put Mobile One Synth in my rear-end when I last changed the fluid.

One more question, why exactly does one require synth and the other not?

Thanks - Patrick :D

The Auburn was an SLP option from 99-02. The Auburn is a cone type posi and relies on friction; synth. changes the friction characteristics of how the posi works. The Torsen is a gear bias operating diff and the fluid being synth or dino doesn't matter (unless you're talking about a T-2R which wasn't put in Z28's ;)

[jumpcable]

Hey...thanks for the info. That helped out a lot. :D

[b3av3r]

I change both at about 15,000-20,000 miles depending on my driving and if I have the time to do it. I have always used redline in the rear end and have never had a problem with any noises or such.

I use Royal Purple ATF fluid for the tranny, the synchro max stuff. Thunder Racing recommended it to me and said it was the only synthetic you can run in this tranny. I always notice a little quieter running tranny (I think I need a rebuild anyway) and smoother shifts right after changing the tranny fluid.

Both are pretty easy to change but both are a pain to fill back up.

[99huggerorangeZ]

i am going to be changing the fluid in my m6 and in my rear diff how many quarts do i need for the tranny and rear diff?

[jmd]

Originally posted by 99huggerorangeZ
i am going to be changing the fluid in my m6 and in my rear diff how many quarts do i need for the tranny and rear diff?

3.5 pints for the differential.

[jmd]

Originally posted by 99huggerorangeZ
i am going to be changing the fluid in my m6 and in my rear diff how many quarts do i need for the tranny and rear diff?

M6:

http://www.ls2.com/forums/showthread.php?s=&threadid=9

leads to

http://www.ls2.com/boggs/torques/enginetorques.htm

leads to

http://www.ls2.com/boggs/torques/mm6.htm

which gives
3.9L, 4.1qt

[2REDGMC]

Originally posted by killer01ws6
you don't have to put synth in the rear of the torsen, but the reason you don't want it in the auburn is the clutch packs will slip and chatter hurting you instead of helping.

That is not correct. The base stock of a gear oil has vary little to do with the performance of the oil. The additives do the work and if the additives are the same ( and in most cases they are ) then the oil will perform the same.

Some of the better quality synthetics contain the friction modifier needed for the clutch pack and if you add more you will damage the clutch pack. So be care full and make sure you need to add the friction modifier before doing so.

[killer01ws6]

Originally posted by 2REDGMC
Some of the better quality synthetics contain the friction modifier needed for the clutch pack and if you add more you will damage the clutch pack. So be care full and make sure you need to add the friction modifier before doing so.

True, and I do check that.
but good info to pass for someone thinking about a change, which is why I was pasing the info as well.

[2REDGMC]

What I am saying is that you can use a synthetic in an Auburn differential.

[killer01ws6]

Originally posted by 2REDGMC
What I am saying is that you can use a synthetic in an Auburn differential.

I understand that.

And seeing I know where you work;)
I will let your word speak for its self. But the reason I did not recommend it, is I have read many posts of people having problems with it. Now You manybe right on the money with that they added the additive into a oil that had it already.

I have not had a auburn, all of mine have been torsens.

Again, I would say you are more up on that than I.

[BlackbirdWS6]

hey, got a 97 T/A changing the trans and rear end fluid this sat, i ordered royal purple syncromax for the trans and got royal purple 75w90 for the rear end. do i need the additive with this fluid in the rear for the posi?

[Blacker]

You cannot use synthetic on a Auburn Differential and that is directly from Auburn, the manufacturer. With the Auburn Differential, use 80W-90 Non Synthetic Fluid with 2 ounces of GM Limited Slip Additive.