C6 Fluid

[My65]

I know the newer C6's use Dex III but does/has anyone used the old Type F? I have a newer tranny ('80-'95) and am using the Dex III but seem to be losing power and fluid. I cant' find a leak, and there is no puddle under the truck. I know the Type F is thicker and stickier.

[Johnny Canuck]

I have heard it is a trick to use some type F in them before Jason. Maybe a litre? I am not sure. the F type is more viscous and supposedly cures just what you are saying ails ya.

[DanSanDiego2000]

If you are losing fluid, pull the vacuum hose that leads from the transmission vacuum modulator to the carburetor. Pull off both ends, and you may find transmission fluid running out of it. If the vacuum modulator goes bad, your engine vacuum can suck fluid out of the trans, and burn it out through the tailpipe.

If you find the modulator to have a leak, a replacement is easy to locate and install.

Good luck.

Dan

[DanSanDiego2000]

And FYI, the Type F fluid from days gone by was a very stripped down version of the Dexron III and Mercon V of today. Racers using GM trans with Dexron II fluid opted for the type F fluid because it was thinner, not as viscous or sticky, and would allow a trans to upshift sharply and firmly. The additives found in modern fluids served to cushion shifts, and that may be why your trans feels mushy. Hondas, Mitsubishis, Chryslers and Toyotas almost exclusively use a 7176 highly friction modified fluid. These transmissions are designed to use this sticky, thick, viscous fluid as a cushion, ease shifts, and add comfort to driving. C6s, TH400s and most muscle car era transmissions used wave springs, accumulators and other tricks to eliminate the BANG from the shift.
As I mentioned before, a fluid flush, replacing your modulator (if leaky), a filter replacement, and a complete refill of proper type fluid, and you may find a big improvement.
Good Luck.
Dan

[My65]

Thanks guys...