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Hello all, I have a small but annoying persistent ATF fluid leak which I thought was the transmission pan and/or gasket but wasn’t. It is coming from above. Is there a more “high tech” way of finding these stubborn leaks? I’ve even thought of pressurizing the transmission through the dipstick tube with air and checking underneath to to see if it’s oozing out anywhere but I’m not sure if it’s safe to do that. I added a bottle of leak finding dye to the transmission and drove it for 300 miles and checked but that didn’t help either. Everything above the pan on the transmission towards the front of the vehicle is slightly wet with ATF. I’m thinking it could be where the dipstick goes into the transmission but I’m not %100 sure.
The Vent has a rubber hose that connects to the metal tube that runs forward and loops up the bell housing and back down to drivers side by shifter
The up and down loop is to prevent fluid/vapor from coming out the vent, and dripping onto the ground, it collects in the lower part of the tube and runs back into the trans
If you overfill trans it will push more fluid out the Vent
If trans gets too hot more fluid comes out the Vent, i.e. Fluids expand when heated
But in your case it could be the rubber Vent hose come off or is rotted and cracked
There is also the possibility its not ATF at all, but oil from valve cover leak, running back along the top of bellhousing and trans
You can add UV Dyes to trans fluid, won't hurt anything, then after a week or so check for signs of the dye with UV light
The Vent has a rubber hose that connects to the metal tube that runs forward and loops up the bell housing and back down to drivers side by shifter
The up and down loop is to prevent fluid/vapor from coming out the vent, and dripping onto the ground, it collects in the lower part of the tube and runs back into the trans
If you overfill trans it will push more fluid out the Vent
If trans gets too hot more fluid comes out the Vent, i.e. Fluids expand when heated
But in your case it could be the rubber Vent hose come off or is rotted and cracked
There is also the possibility its not ATF at all, but oil from valve cover leak, running back along the top of bellhousing and trans
You can add UV Dyes to trans fluid, won't hurt anything, then after a week or so check for signs of the dye with UV light
Thank you very much. I never knew there was such a vent. I’ll have to crawl under and check later this afternoon. I’m assuming the only way to replace that plastic tube is to drop the whole transmission? And it definitely is ATF. It’s red in color. My transmission may be slightly overfilled because I checked yesterday and it was about a 1/4” over the crisscross grid section on the dipstick, but then again it was a 100 degree day and I just got off the freeway when I checked it.
You could replace it by feel, no clamps on it, just snug fit
And the metal loop tube may not even be there if trans was ever out before, lol, people forget to put it back in and then say, "well......never mind, I'll put it back later", and of course later never comes
Transmissions need the Vent but not the loop to work
Off-roaders extend the Vent hose up higher for water crossings, same as the axle vents
09-13-2021
