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Now that my car (Z51) is at 20k miles and nearing 2 years old, I figured it was time I should change out the transmission (M7) and rear differential fluids.
Tremec recommends a Dexron III ATF fluid in the transmission, but the dealer parts counter tried to sell me something called ACDelco Manual Transmission Fluid. I decided to just skip the confusion and order the tried & trued Redline D4. I've been using Redline transmission fluids for 15 years and always been very satisfied with the shift quality. I was able to get a gallon jug of it on Amazon for under $50.
For the rear differential I went with the factory ACDelco LS 75W-90 fluid, which I was also able to get 3 quarts of it on Amazon at a good price (with same-day delivery).
I put Amsoil synthetic in both. The GM fluid in the diff is not a synthetic and at 3k miles was already black so I drained it out and put in the Amsoil gear oil for peace of mind. Same in the trans.
Using Redline D4ATF in the trans and Mobil 1 75/90 synthetic LSD in diff for a year with 6 track days--happy with both.
Interesting, this is good to hear. I was tempted to try the Mobil 1 in the diff, but read conflicting reports on whether or not it contained enough LSD additive. The Mobil 1 is tempting because it's cheaper, easier to source, and semingly of higher quality.
I put Amsoil synthetic in both. The GM fluid in the diff is not a synthetic and at 3k miles was already black so I drained it out and put in the Amsoil gear oil for peace of mind. Same in the trans.
Now that my car (Z51) is at 20k miles and nearing 2 years old, I figured it was time I should change out the transmission (M7) and rear differential fluids.
Tremec recommends a Dexron III ATF fluid in the transmission, but the dealer parts counter tried to sell me something called ACDelco Manual Transmission Fluid. I decided to just skip the confusion and order the tried & trued Redline D4. I've been using Redline transmission fluids for 15 years and always been very satisfied with the shift quality. I was able to get a gallon jug of it on Amazon for under $50.
For the rear differential I went with the factory ACDelco LS 75W-90 fluid, which I was also able to get 3 quarts of it on Amazon at a good price (with same-day delivery).
Thoughts? Comments? Suggestions? Discussion?
For what it's worth, RPM Transmission recommends Valvoline full synthetic 75-90 in the diff with a bottle of gm friction additive and Royal Purple Synchromax manual transmission fluid in the tranny.........They also said they do not and will not recommend Royal Purple 75-90 diff fluid..........
My friend just lost his rear end with Royal Purple, too many bearing failures seen at shops too, best place for it is on the shelf or in a trash can, just don't let the EPA see you dispose of it...
My friend just lost his rear end with Royal Purple, too many bearing failures seen at shops too, best place for it is on the shelf or in a trash can, just don't let the EPA see you dispose of it...
Wow so what u say is the best I should put in whenever I change it
I change my differential fluid on my 2014, and used the GM fluid that comes with friction modifiers already in it...
Technically, no one makes Dexron III fluid anymore, and I have been using the GM Manual Transmission fluid (same stuff)..
Some club members tried a full synthetic on older models and had some shifting problems. They went back to the stock fluid and problems went away... GM stocks only one manual transmission fluid for C5, C6, and C7 now.
Last edited by TEXHAWK0; Oct 19, 2015 at 03:13 PM.
Interesting, so it's likely the ACDelco Manual Transmission Fluid is the correct fluid, just under a different name since it's only sold for the manual transmission cars, not the ones equipped with automatics (since those are all running Dexron VI now it appears).
Interesting, so it's likely the ACDelco Manual Transmission Fluid is the correct fluid, just under a different name since it's only sold for the manual transmission cars, not the ones equipped with automatics (since those are all running Dexron VI now it appears).
Correct, automatics now use Dexron VI.
My 2011 Camaro even uses Dexron VI in the power steering. (Of course, now cars are going to electric power steering instead of hydraulic)
Drivetrain fluids - Who's using what?
