Scotty,
I have a 2012 Toyota Sienna (FWD) base model. I replaced transmission fluid but made the mistake of putting in too much. When I was driving in a highway, check engine light came on and transmission fluid leaked onto engine compartment area. It is a sealed transmission with no dipstick. I'm wondering where did the transmission fluid come out of. Is there a vent port in the transmission where transmission fluid can escape if pressure builds? I wanted to rule out that my transmission seals were not compromised due to overfilling. Thank you.
James L.
@bumperbad
@bumperbad
Every transmission has a vent port, it is not 100% sealed from the atmosphere. Same with engines but the air is circulated back into the engine. (PCV: Positive Crankcase Ventilation)
Sounds like you severely overfilled the transmission. The transmission has to be at a certain temperature and the van must be level while checking the ATF level.
@bumperbad
you have to remove your fluid to do the job right. you have to put exact quantity or you can loose youre transmission
I agree with the others. Since your transy is overfilled, you need to warm up your engine to the point where the fluid is within a certain temp range (105-110F if I recall correctly) and then take out your transmission plug. Let it drain down to the point where you just have a trickle of fluid coming out. Do this with the engine running. There's a straw in the bottom of the transy pan which will allow the fluid to just trickle out when you have the right amount of fluid in there at that specific temperature.
Every transmission has a breather when you over fill it they will escape from there but since you need to pump yours in just drain it and put 5 quarts back in with the car turned on
