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This is a subject of much debate on several forums, but GM released a bulletin about Dexron III being replaced by Dexron VI: Bulletin #04-07-30-037E: Release of DEXRON-VI Automatic Transmission Fluid (ATF).
According to the bulletin:
"MANUAL TRANSMISSIONS / TRANSFER CASES
The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON®-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid."
That is what I put in my 2001. Others have had success with other options as well. I'll let them chime in with their experiences.
Plain and simple, if you have a manual transmission, you need to keep using what was called Dexron III fluid. That can now be called by several names, but it is the older higher viscosity ATF fluid.
Do NOT use the newer Dexron VI rated lower viscosity automatic transmission fluid in C5, C6 or C7 Tremec manual transmissions.
This is a subject of much debate on several forums, but GM released a bulletin about Dexron III being replaced by Dexron VI: Bulletin #04-07-30-037E: Release of DEXRON-VI Automatic Transmission Fluid (ATF).
According to the bulletin:
"MANUAL TRANSMISSIONS / TRANSFER CASES
The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON®-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid."
That is what I put in my 2001. Others have had success with other options as well. I'll let them chime in with their experiences.
This is what I use in my 2000, shifts like butter.
I'm currenlty in the rabbit hole on this topic as I want to replace the fluid in my '99 manual trans.
The 8861800 seems hard to get, but may be the ideal choice for the older C5s with the paper syncros if you can find it. I've ordered it a few times from different places and was delivered 19540137 instead.
Had the Torque Drive in my garage, but didn't use it because it is synthetic.
Intrigued by the Mobil ATF as I've seen that posted before.
Has anyone run Valvoline 883786. This was availabel at local box store. Says Dex III, and recommended for vehicles before 2006.
I'm currenlty in the rabbit hole on this topic as I want to replace the fluid in my '99 manual trans.
The 8861800 seems hard to get, but may be the ideal choice for the older C5s with the paper syncros if you can find it. I've ordered it a few times from different places and was delivered 19540137 instead.
Had the Torque Drive in my garage, but didn't use it because it is synthetic.
Intrigued by the Mobil ATF as I've seen that posted before.
Has anyone run Valvoline 883786. This was availabel at local box store. Says Dex III, and recommended for vehicles before 2006.
That is exactly what I used a month ago for my 1998. Think it was 3.5 quarts or so? pretty much took the whole jug then ran out the fill hole. Shifts great! I was having a hard 1-2 shift when cold and that went away after the fluid change. No leaks a month later.
I'm currenlty in the rabbit hole on this topic as I want to replace the fluid in my '99 manual trans.
The 8861800 seems hard to get, but may be the ideal choice for the older C5s with the paper syncros if you can find it. I've ordered it a few times from different places and was delivered 19540137 instead.
Had the Torque Drive in my garage, but didn't use it because it is synthetic.
Intrigued by the Mobil ATF as I've seen that posted before.
Has anyone run Valvoline 883786. This was availabel at local box store. Says Dex III, and recommended for vehicles before 2006.
atf in a Manual transmission
Last edited by Smitty's; Apr 30, 2025 at 12:59 PM.
Reason: Add info
Dexron iii
