bc_stang

yeah i made a mistake when i replaced clutch in my car.i put gear oil in my tranny and noticed gears were a bit hard to engage,specially when car was cold in the mornings.called my buddy and he said i was suppose to put normal atf fluid.after that it was just like new car.all the gears engaged without any effort.

also i dont know about what year they switched to atf fluid but the tranny's that use atf fluid have less tolerances inside the gears so its easier for atf to get in bearings,bushings as compared to gear oil .tranny's that use gear oil has bigger tolerances so that thicker fluid would get in places easier...i dont know if its true in ford tranny's but thats what its suppose to be.

kartrcr7789

it probably has gear oil in it right now. as you said gear oil gunks up and sludges in the winter, this is a new england car, and it doesnt help it had been sitting a little while.

silver91gt

you will ruin your tranny with gear oil.
not now, but there will be waaaaay more wear on your gears.
so instead of the tranny lasting 200000 miles it will mabye last 25-40k.
your owners manual should say to use only dextron 3 ATF.
I swear by mobil 1 synthetic ATF.
by changing from regular to synthetic ATF I gained a tenth in the quarter.