Overfilling Tranny

[Rookie2]

I've noticed from time to time that under heavier throttle, the tranny shifts kind of hard and jolty. Pulled the dipstick out the other day after it was warm and noticed the tranny fluid was 3/8" or so above the upper tick of the hot zone. Obviously that's no good, but any thoughts on what problems this will cause?

Thanks,
Rookie2

 

[archie]

Somebody correct me if I am wrong, I think that if it's too high the fluid will cause pressure to build up and a could cause leaks in your gaskets. This is because some space usually occupied by air and if the air does not compress( or the cavity is filled with fluid) the pumps will cause excessive pressure to build up. I think this could overwork the pumps also and instead of recirculating fluids it might just slosh around in one area. I think that this could apply to overfilling the engine motor oil also.
If you haven't had a record of changing the trans fluid, you might want to change it.

 

[John E Davies]

I don't think it will cause any operational problems - the real risk is that if you get the tranny really hot (climbing a mountain in summer with a trailer, for example) the excess fluid will puke out and make a smokey stinky mess.

Also, if you have extended breathers and you teed your tranny vent line into the diff and transfer case vents, you will pump ATF into those components if the tranny pukes fluid. This is the reason I kept my extended tranny vent seperate, with a seperate filter.

It's dead simple to correct a slightly overfilled tranny - just pull the drain plug _carefully_ while wearing a rubber glove and let about a pint out, then recheck. Don't drop the plug into the drain pan or you way end up losing 4 or 5 quarts.

John

 

[ultimauk]

Somebody correct me if I am wrong, I think that if it's too high the fluid will cause pressure to build up and a could cause leaks in your gaskets. This is because some space usually occupied by air and if the air does not compress( or the cavity is filled with fluid) the pumps will cause excessive pressure to build up. I think this could overwork the pumps also and instead of recirculating fluids it might just slosh around in one area. I think that this could apply to overfilling the engine motor oil also.
If you haven't had a record of changing the trans fluid, you might want to change it.

"This is because some space usually occupied by air and if the air does not compress( or the cavity is filled with fluid) the pumps will cause excessive pressure to build up."

I know less than most, but wouldn't the said air escape through the dip stick tube?

 

[archie]

I thought about the dipstick but if the pump pressure was going in another direction then excessive pressure could build up. I'm no expert in trannies so hopefully somebody could contribute to the discussion to clarify if this actually occurs.