T56 fluid
tag right on the trans says dexron 3 atf , if its stock with the paper blocker rings I wouldn't use anything else... if it has been upgraded then there many other fluids that will get tossed around in these conversations from synchromesh to all the aftermarket quality synthetics.
Stick with AC Delco part number 88861800 from the dealership. It's the oem replacement for dextron iii. Might cost an arm and a leg, but is definitely worth it. Was using it for the lifetime of my '99 z28's t56 until i switched to royal purple and destroyed my trans..
Also dextron vi can be used in replacement for dextron iii.
Also dextron vi can be used in replacement for dextron iii.
12 Second Club
Joined: Sep 2005
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From: Bucks County, Pa.
Stick with AC Delco part number 88861800 from the dealership. It's the oem replacement for dextron iii. Might cost an arm and a leg, but is definitely worth it. Was using it for the lifetime of my '99 z28's t56 until i switched to royal purple and destroyed my trans..
Also dextron vi can be used in replacement for dextron iii.
Also dextron vi can be used in replacement for dextron iii.
Also, the Dex 6 stuff is WAY TOO THIN for use in a T56, unless you live inside the Arctic Circle, in the winter time!!
TECH Enthusiast
Joined: Nov 2011
Posts: 587
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From: Connecticut SE shore
Tremec's recommendations as of a couple years ago were Dexron ATF 3 or Mobil 1 synthetic ATF. Those were the only ones they claimed had enough data to show they worked properly. If you review older threads you'll find everything from Synchromesh, Amsoil ATF, etc. You should not have the paper block rings in your 2002, unless some rebuilt the trans with older materials only seen in stock '98's to 00's.
ATF 3 is simple and it works, just like the label attached to your transmission recommends. I put in regular Valvoline ATF 3 when I did mine as I don't race or track my car. For a car that is sometimes tracked or run hard in hot weather there might be some advantages to higher end products. I must have read old threads on here for hours before I finally came to the conclusion that ATF 3 was the safest and most logical choice for what I do. And my trans has the paper blocking rings that could swell under the wrong type of fluid. The factory fluid had been in my car for 13K miles/13 years. After changing it out I felt or heard no perceptible difference in performance. Some people report notchier cold T56 operation with some of the synthetics....once warmed up it's fine.
One source recently told me that the paper/cellulose blocker rings on the 1998-2000 Tremec T56 manual transmissions are actually made of kevlar/graphite/cellulose composites, similar in composition to some clutch disc material. It's not quite just "paper."
ATF 3 is simple and it works, just like the label attached to your transmission recommends. I put in regular Valvoline ATF 3 when I did mine as I don't race or track my car. For a car that is sometimes tracked or run hard in hot weather there might be some advantages to higher end products. I must have read old threads on here for hours before I finally came to the conclusion that ATF 3 was the safest and most logical choice for what I do. And my trans has the paper blocking rings that could swell under the wrong type of fluid. The factory fluid had been in my car for 13K miles/13 years. After changing it out I felt or heard no perceptible difference in performance. Some people report notchier cold T56 operation with some of the synthetics....once warmed up it's fine.
One source recently told me that the paper/cellulose blocker rings on the 1998-2000 Tremec T56 manual transmissions are actually made of kevlar/graphite/cellulose composites, similar in composition to some clutch disc material. It's not quite just "paper."
Last edited by Firebrian; Oct 23, 2015 at 12:12 PM.
12 Second Club
Joined: Sep 2005
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From: Bucks County, Pa.
The synthetic based ATFs should NOT be any notchier, or grind any more than the mineral based ATFs, regardless of blocker ring material.
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Verdad Gallardo TECH Enthusiast
Joined: Nov 2011
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From: Connecticut SE shore
Stick with AC Delco part number 88861800 from the dealership. It's the oem replacement for dextron iii. Might cost an arm and a leg, but is definitely worth it. Was using it for the lifetime of my '99 z28's t56 until i switched to royal purple and destroyed my trans..
Also dextron vi can be used in replacement for dextron iii.
Also dextron vi can be used in replacement for dextron iii.
Just did a 5K mile/4 year trans fluid change on my '99 SS and went with the GM 88861800. One of my local auto shops had it for around $6/qt which was fine for me. I did plenty of research again and decided not to go with a synthetic or a synchromesh because of the cellulose composite blocker rings in my syncro's.
I reviewed a UOA on a 6 speed Vette using ATF and that sheared down quite a bit in under 10K miles (operating viscosity of 7 cSt to 5 cSt). DEX VI (ATF LV) or Valvoline Max Life ATF have viscosities of around 6.0 cSt which is too thin imo. While the dedicated MTL's have a stronger AW and EP additive packages (and viscosities of 8 to 12), some of them can interfere with efficient synchro operation and wear. The best AW packages seem to be in the Amsoil, Redline, Honda, Mobil 1, and other boutique ATF's. Since I'm changing out in under 5K miles, I'll stay with the GM stuff for now.
Fwiw, I saw no difference in operation from the 5K mile Valvoline conventional Dex 3 and the newly installed GM 88861800.
