My G8 GXP is due for a fluid swap in the TR6060 manual. I remember the mag mentioned a suggested fluid upgrade for the TR6060 in the Corvette a while back. For the life of me, I can't find the article. I'd love to smooth out the 1-2 shift in mine. Has anyone had good luck with Redline, Royal Purple, Mobil1, etc? GM calls for Dexron III.
I have never had any luck with Royal Purple anything.
I've always used Dexron VI with no issue. Whatever synthetic ATF your auto parts store has on hand will do.
Fluid will never fix a worn or damaged synchronizer, you will need to rebuild the trans to fix that, or spend an extra half second being gentle with the shift. That said every TR6060 I have driven was not exactly buttery smooth, even new ones, so you may need to just accept that a transmission with the mass to accept massive torque will never shift as smoothly and lightly as a Miata.
I only ever used Dex/Merc in my T56, so I can't speak to what different fluids do for them, but in my experience with all the manuals I've had, none of them do anything.
My current M5OD (even when the clutch does fully disengage), I went through a bunch. It had MerconV in it (at least if I believe the receipt from the PO) and I wanted to treat it to something better, so I did Royal Purple's synchromax. No change. The M5R2 in my friend's F150 got Redline. No change. I eventually swapped my RP synchromax for Pennzoil's Synchromesh, which is what all the Ranger guys swear by. No change.
Normally, I get a swell of pride when I upgrade fluids... like if I do a Mobil 1 oil change because it was on sale, I feel like a my car is hugging me. So far my experience with MT fluids is, "as long as it's close and not water, it will shift the same no matter what you put in it."
Obviously paying attention to what fluid it actually calls for. I don't put gear lube in with brass synchros or anything like that.
ATF is actually not the greatest for MTs. It was one of those things that manufacturers did to streamline costs. It works, it's already on the shelf, it's cheap, and it reduces the risk of a ham-fisted service tech getting the wrong stuff in there. It's actually not "right" but it works fine.
The main things you need to focus on is additive package (compatible with your synchros) and viscosity. As long as you stay within those parameters, and as long as it's oil, go for it.
The M5R2 in the Supercoupe seemed to like Pennzoil Syncromesh. It didn't help a lot though. That was a pretty notchy transmission on the best of days.
The G35 loved the switch to Nissan OEM oil. It was chunky into 3rd and 5th before. Now it's as smooth as butter unless it's cold.
What does GM use and do they sell it? That's probably what I would go with.
Viper guys just run the stock stuff and swap it when we track for wear. I see no need to go crazy on expensive fluids for the 6060.
I've found fresh fluid to make more difference than brand of fluid.
Thanks guys. I know it's never going to be smooth shifting. It hasn't been since new. I'm like Curtis, given the opportunity, I'll upgrade fluids. It seems like in this case, there's probably not much benefit to be found.
Interestingly, the owners manual doesn't mention the fluid in the manual transmissions at all. It looks like the GM part number is 88861800, Manual Transmission and Transfer Case Fluid. From what I can tell, it just Dexron III-H with a different label.
I was just researching this for the trans in my corvette. Everyone recommends amsoil or Royal purple. However I found the AC delco stuff for cheap so that made my decision easier.
G8MikeGXP said:My G8 GXP is due for a fluid swap in the TR6060 manual. I remember the mag mentioned a suggested fluid upgrade for the TR6060 in the Corvette a while back. For the life of me, I can't find the article. I'd love to smooth out the 1-2 shift in mine. Has anyone had good luck with Redline, Royal Purple, Mobil1, etc? GM calls for Dexron III.
I would run whatever your available synthetic that meets dexron III standards.
Not all 6060's are created equal, each manufacturer specs them slightly differently. I believe they varied the syncro composition, even changing by year for some makes.
I ran amsoil in a Dodge 6060 (challenger RT) and it smoothed the shifts up a little in warm weather, but it called for ATF +4. I recall there was some change from double to triple syncro cones and they were carbon fiber (I could also be remembering incorrectly). The fluid type is important for what is spec'd for this reason.
That car is long gone from my ownership, but I always thought the shifter isolation system left a little to be desired: are your motor mounts good, shifter bushings good? If so I would recommend any synthetic DexIII, give it a run, and if its worse just swap back to the GM fluid.
G8MikeGXP said:Thanks guys. I know it's never going to be smooth shifting. It hasn't been since new. I'm like Curtis, given the opportunity, I'll upgrade fluids. It seems like in this case, there's probably not much benefit to be found.
Interestingly, the owners manual doesn't mention the fluid in the manual transmissions at all. It looks like the GM part number is 88861800, Manual Transmission and Transfer Case Fluid. From what I can tell, it just Dexron III-H with a different label.
When you buy a new trans from Tremec, they tell you to use some flavor of Dexron.
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