Six-Speed Trans Fluid?
Thread Starter
Instructor
Joined: Oct 2009
Posts: 119
Likes: 1
From: Warner Robins GA
Six-Speed Trans Fluid?
I have a '99 with manual trans. I've heard about the paper blocker rings and how synthetic fluids will ruin the trans. But I've also heard some synthetics won't harm the paper blockers. I like Amsoil products, so is there a synthetic fluid they produce that will work?
Pro
Joined: Apr 2005
Posts: 666
Likes: 5
From: Mt. Pleasant SC
That is one of the biggest myths propagated on this forum. I have a 2000 w/6-spd manual and have had Mobile 1 synthetic ATF in my tranny for over 50k miles now with no issues whatsoever. Your manual recommends DEXRON III ATF. No mention of any warnings against using synthetic. I would never do anything risky on my C5 and I have zero concerns about using synthetic ATF.
Pro
Joined: Dec 2009
Posts: 606
Likes: 1
From: Waco Texas
I have a '99 with manual trans. I've heard about the paper blocker rings and how synthetic fluids will ruin the trans. But I've also heard some synthetics won't harm the paper blockers. I like Amsoil products, so is there a synthetic fluid they produce that will work?
Instructor
Joined: Apr 2010
Posts: 179
Likes: 2
From: ramona california
Drifting
Joined: Feb 2007
Posts: 1,793
Likes: 7
From: Santa Maria Ca.
I used Mobil 1 ATF in my '98 MN6 for about 6 months,and it didn't really help the shifting at all-it was "clunky" or "notchy" going into any gear,so I decided to go with what the tag on the fill plug said,drained the Mobil 1,and filled it up with Valvoline Dexron III (the cheap stuff).and it's been shifting like a Vette should every since.
I may be an isolated case,but my tranny definitely did not like the Mobil 1.
I may be an isolated case,but my tranny definitely did not like the Mobil 1.
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Le Mans Master
Joined: Jun 2006
Posts: 6,979
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From: Wichita KS
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
GM TSB states that vehicles previously using Dexron III should now use P/N 88861800 Labelled Manual Transmission and Transfer Case Fluid.
My local speed shop recently installed Amsoil ATF and I immediately began to experience a gear whine when shifting around 3,000 RPM.
So I'm changing to the new GM P/N.
Le Mans Master
Joined: Aug 2000
Posts: 6,273
Likes: 14
From: Austin TX
GM no longer sells Dexron III and I've read that the H spec that other brands sell does not match the H spec that GM's Dexron III met. In other words, the after market Dexron III is not the same as GM's was.
So, where do you folks buy Dexron III that is equal to GM's?
Tks for your replies.
So, where do you folks buy Dexron III that is equal to GM's?
Tks for your replies.
