Changing Tranny Fluid
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
From the technical FAQ:
Fluids
Doug Nash 4+3 - use standard 75-90 wt gear oil, and Dextron III ATF in the overdrive.
Automatics, use ATF - Dextron III.
Rear differencial - 75-90 wt gear oil, 2 bottles of GM Limited Slip Differential Additive.
ZF 6spd - The GM oil (available from GM with part number 1052931; superceded by GM part number 12345349) and the Castrol Synthetic Formula TWS 10W60 (available from BMW with part number 0751009420). Other types have been used/suggest/recommended, including ATF, but the Forum concensus is that the two listed above are the SAFEST solutions. Click for the C4 Guru Tech Tip - Changing ZF6 Fluid
Coolant - Prior to 1995, all Corvettes came with GREEN coolant. Do not mix Dex-Cool with conventional green coolants, or it will cause the mixture to become jelly. It's a real mess to clean up. There are new coolants that are compatible both ways, they are ok.
Engine oil - It does not matter the year, but any of the good quality Synthetics are worth their weight in black gold. Mobil 1, Valvoline Synpower, etc; 5W-30 is the recommended weight.
Oil Filter - Premium brand, K&N, AC Delco Gold, Mobil 1. The K&N has a nut on the end for easy install and removal.
Brake/Clutch Fluid - Valvoline Synpower.
Power Steering Fluid - Valvoline Synpower
Doug Nash 4+3 - use standard 75-90 wt gear oil, and Dextron III ATF in the overdrive.
Automatics, use ATF - Dextron III.
Rear differencial - 75-90 wt gear oil, 2 bottles of GM Limited Slip Differential Additive.
ZF 6spd - The GM oil (available from GM with part number 1052931; superceded by GM part number 12345349) and the Castrol Synthetic Formula TWS 10W60 (available from BMW with part number 0751009420). Other types have been used/suggest/recommended, including ATF, but the Forum concensus is that the two listed above are the SAFEST solutions. Click for the C4 Guru Tech Tip - Changing ZF6 Fluid
Coolant - Prior to 1995, all Corvettes came with GREEN coolant. Do not mix Dex-Cool with conventional green coolants, or it will cause the mixture to become jelly. It's a real mess to clean up. There are new coolants that are compatible both ways, they are ok.
Engine oil - It does not matter the year, but any of the good quality Synthetics are worth their weight in black gold. Mobil 1, Valvoline Synpower, etc; 5W-30 is the recommended weight.
Oil Filter - Premium brand, K&N, AC Delco Gold, Mobil 1. The K&N has a nut on the end for easy install and removal.
Brake/Clutch Fluid - Valvoline Synpower.
Power Steering Fluid - Valvoline Synpower
I guess I will stick with regular tranny fluid.
