who's dumped the atf ...

[bonnie john]

from their LS1/6 speed manual and gone for a "real" gear oil ?

what did you do?
what oil did you use?
how was the end result?

i'm changing all the fluids in a new (to me) ozzy gm V8 and want a more robust lube

 

[sciphi]

I'd stick with the ATF. It's designed to run on it, even being a manual transmission.

That being said, buy the best ATF you can afford.

 

[mva]

I am currently running Mobil synthetic ATF in my 2000 Z3M manual trany; ATF is recommended by BMW. Shifting improved over the stock fluid.

Next change I am going to try Amsoil 5W30 MTF or Royal Purple Syncromesh fluid.

There are number of BMW owners reporting very good results with Amsoil 5W30 MTF.

Check out this thread for extensive information on this topic:

http://forums.bimmerforums.com/forum/showthread.php?t=1076268

 

[MonumentOiler]

The factories have "gear oil" available to them and still choose the ATF.

A full syth ATF like Amsoil's ATF/ATE or Redline's D4/D6 seems like a natural substitute.

A 5w30 gear oil is not going to be the same viscosity wise.

 

[Jason2007]

I thought GM specified Synchromesh fluid for the Tremec 6 speed?

 

[NewC6]

GM just specified their Manual Transmission fluid for those trannys that used Dexron III since Dexron VI is not to be used for the fill fluid, "damage could result". Supposedly this is the new fluid of choice for 97-2010 corvettes with manual trannys.
I am giving serious consideration to going with the Amsoil MTF in my 2008 Z06.

 

[Tremo]

Your tranny is a Tremec T56. It's a good 6-speed, and can handle 450 ft pounds of torque. Tremec says to use Dexron 3 ATF in their transmissions. Do yourself a favor and listen to what the manufacturer is telling you.

There is ONE alternative. Royal Purple Synchromax. It's a manual tranny oil for those which call for ATF. I run this in my T5, works great.

GM buys their manual trannys from Tremec. So does Ford.

If you put regular gear oil in a Tremec you are effing up.

 

[Jason2007]

I must agree on the RP Synchromax reccomendation. My Mustang has the Tremec 3650 trans and it calls for ATF. I have put in SYnchromax and it has never shifted as smooth as it does now. I tried Mercon V, Mobil 1 Synthetic ATF before I finally settled on RP.

 

[mechtech2]

Why does the same logic not apply that Mfrs have RP products available to them, and don't use them??
There are many reasons trannys are spec'd for ATF. Being the absolute best fluid possible for a synchronized manual trans is not one of them.

 

[bonnie john]

it's a GEARBOX, NOT AN AUTO

by my understanding, it has gears, roller and ball bearings, splash lube, lower temps, syncros and can be user-abused by lugging, speed shifting and shock loading, all of which in the past have GENERALLY called for a fluid with mild to wild EP additives

an auto, by my understanding, has clutches, an oil pump, higher operating temps, less shock GENERALLY with the engagement/shift operation

so, back to my question ...

 

[nfs480]

They know it's a gearbox, that's what they're talking about

 

[JakeR22]

Originally Posted By: nfs480
They know it's a gearbox, that's what they're talking about


LOL. No kidding.

Run something else if it make you feel like a rebel.

 

[Tremo]

No kidding. I'd say that Tremec knows better than anyone else that it's a gear box. They say use ATF. Somebody here say he's smarter than the guys at Tremec who made the thing? Somebody is smoking something funny.

Got an idea for you buddy, why don't you give the guys at Tremec a call?

Too much EP adds or friction modifiers will eff-up the synchros.

If you just can't bring yourself to use the Tremec recommended ATF, then use RP Synchromax. Or a mix of synthetic ATF and Synchromax.

I think the ATF usage started when they modded the T5 tranny into the so-called "world-class T5". I understand (could be wrong) that early T5s used gear oil, then the WC-T5s called for ATF. I heard it was because they changed some clearances and openings inside, and now needed a thinner oil. I have one of those so-called WC-T5s in my old IROC. I run 50/50 Synchromax and M1 ATF. I can tell you it shifts great and it has 160k on it.

To get the best scoop on these Tremecs, I'd go to the thirdgen.org web site and ask the guys there, they have a LOT of experience with Tremec boxes. I also suspect they'll tell you not to use gear oil in a T56.

 

[defektes]

AMSOIL SYNCROMESH!

better shifting, less noise, happy customer.

I have used GM, and Pennz. synchro aswell.

As far as RP I read some UOA here that showed the RP shearing at very low miles.

 

[Ken2]

An automatic transmission doesn't have gears, bearings, abusive operators who change direction while still rolling...everything except synchronizers???????

One of the specialty manual transmission fluids might give better synchronizer operation IF that fluid is recommended for that transmission.