Manual transmission fluid??
#21
Le Mans Master
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You are correct, and for what it's worth, concerning his '81, I would use whatever the service manual said to use. If you don't have a service manual, get one. Haynes and Chilton both make a good one for our cars.
I just mentioned my brother's '97 because some folks seemed incredulous about ATF in manual transmissions, to show that, yes, there are some modern transmissions that use ATF.
Scott
#22
Premium Supporting Vendor
Not trying to inflame the debate, but concur that there are many manuals that use ATF including C5 and C6 Corvette Tremec manuals (my 02 Z06 uses an ATF for the six speed).
For the OP, this is AMSOIL's recommendation for your manual:
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT)
Interestingly, same fluid I use in my diff.
For the OP, this is AMSOIL's recommendation for your manual:
AMSOIL Severe Gear Extreme Pressure Synthetic 75w90 (Product Code SVGQT)
Interestingly, same fluid I use in my diff.
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#23
I know enough about manual trannys to know that a person should use what the manufacturer specifies. The last manual tranny car that I owned or worked on, prior to this vette, was a 1966 GTO that I bought in 1968. Pardon me.
#24
Team Owner
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Race Director
#26
Racer
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#27
Le Mans Master
I refer to my original post on page 1:
"I was aware that some newer manual transmissions used automatic fluid like the 4+3 in the C4's as well as my 1988 Mustang 5.0 manual but have never seen it specified for older 4 speeds like the M22/M21/Borg Warner Super T-10's or in any C3. So are you saying that there are C3 manual transmission cars that had automatic fluid filled from the Factory?"
Like I said , never heard of a C3 manual transmission car ever having ATF fluid in the gear box!!!
"I was aware that some newer manual transmissions used automatic fluid like the 4+3 in the C4's as well as my 1988 Mustang 5.0 manual but have never seen it specified for older 4 speeds like the M22/M21/Borg Warner Super T-10's or in any C3. So are you saying that there are C3 manual transmission cars that had automatic fluid filled from the Factory?"
Like I said , never heard of a C3 manual transmission car ever having ATF fluid in the gear box!!!
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#31
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Terry
#33
Race Director
Not according to the 81 Corvette shop manual,but that's not to say that ATF is not OK or even better in some aspects.
Is using ATF an upgrade ? Most of us certainly don't have a problem upgrading cam shafts,heads,carbs and etc.
I think fuel savings and probably more HP to the rear wheels would be important to some,but being safe with the old heavier lube might be for others.
Is using ATF an upgrade ? Most of us certainly don't have a problem upgrading cam shafts,heads,carbs and etc.
I think fuel savings and probably more HP to the rear wheels would be important to some,but being safe with the old heavier lube might be for others.
#34
Team Owner
Not according to the 81 Corvette shop manual,but that's not to say that ATF is not OK or even better in some aspects.
Is using ATF an upgrade ? Most of us certainly don't have a problem upgrading cam shafts,heads,carbs and etc.
I think fuel savings and probably more HP to the rear wheels would be important to some,but being safe with the old heavier lube might be for others.
Is using ATF an upgrade ? Most of us certainly don't have a problem upgrading cam shafts,heads,carbs and etc.
I think fuel savings and probably more HP to the rear wheels would be important to some,but being safe with the old heavier lube might be for others.
swapped in a OD auto for the ODrive....here, as speeds/distances are much greater than the DC region....
#35
Le Mans Master
Exactly, and my '72 here had a muncie in it, when I got it the thing shifted like a damn old school bus, hard and clunky even when hot, compared to newer cars.....so I changed fluid to 30W synthetic engine oil....it shifted like a new car then, slick as snot on a doorknob.... ran for two years that way, daily driven trip to Florida and back from Maryland, never a issue....
swapped in a OD auto for the ODrive....here, as speeds/distances are much greater than the DC region....
swapped in a OD auto for the ODrive....here, as speeds/distances are much greater than the DC region....
#36
Race Director
#37
Is it true that GL-5 fluid is not compatible with the synchros in a (old) 1959 T 10 manual transmission. That you must use GL-4 fluid. Because the shifting from 1st to 2nd was getting rough on my just rebuild transmission last year, I changed from a 90w GL-5 fluid to AC Delco Manual transmission fluid SAE 75W-85 G-4. The shifting got better last year, just got it back out this year and now I have a bearing whine when I down shift for braking. The AC Delco fluid is thin like ATF, not thick like the old 90w fluid.
#38
Burning Brakes
Just my .02 worth. Beware of using GL-5 in older transmissions unless specified by the factory. It has a higher sulphur content that not only inhibits the sychros from working but also degrades yellow metal parts over time. I have a 06 pontiac solstice that asked for GL-4, I put in GL-5 and it didnt shift for ****, had to get the correct fluid from GM to fix the problem. I need to change the fluid in my 68 but am still looking for a local source for GL-4.
#39
Le Mans Master
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Notice the guy who called everyone a moron is silent now that the Service Manual was shown.
Yes, people make upgrades all across our cars, but the fact that someone on this forum says its a good idea in no way makes it so. This forum, like all forums, have so called experts, and usually they are the ones calling everyone else morons. Pretty typical.
Yes, people make upgrades all across our cars, but the fact that someone on this forum says its a good idea in no way makes it so. This forum, like all forums, have so called experts, and usually they are the ones calling everyone else morons. Pretty typical.
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grady white (09-20-2022)
#40
Drifting
Just my .02 worth. Beware of using GL-5 in older transmissions unless specified by the factory. It has a higher sulphur content that not only inhibits the sychros from working but also degrades yellow metal parts over time. I have a 06 pontiac solstice that asked for GL-4, I put in GL-5 and it didnt shift for ****, had to get the correct fluid from GM to fix the problem. I need to change the fluid in my 68 but am still looking for a local source for GL-4.
That's what I bought but there are a couple others as well.