toyotaoffroad91

hopefully one of you guys could help me out again. i had a perfectly filled AUTO tranny since last week. this morning i felt it acting up again. sure enough i was a little over a quart low. i have zero signs of external leaks. i just added a tranny cooler in line with my existing stock oem one built into the radiator. i see no signs of coolant mixing with the tranny fluid..although i use toyota red coolant i cant see any abnormailites in the fluid. my question is where the hell is the fluid going. i drained my transfer case and there was no mixture there. do you think i have a bad rear seal in the tranny cuase fluid just to sit in the tallhousing??? any recomendations would greatly help me i am stumped on this one!

khaug

You see no signs of coolant in the ATF. Have you also checked the coolant for signs of ATF? That's where I'd expect the ATF to go if there's a leak in the factory ATF-to-water cooler, since you're loosing ATF but don't mention a falling coolant level.

Good luck.

toyotaoffroad91

very good point but not to sure how to find if i have atf in my coolant... acually i just though of one haha .dye!

toyotaoffroad91

i tried something that i think kills that solution. i unhooked my trany lines at the radiator and put a pressure tester on the radiator. pumped up to 13 punds and it held nicely. i wanted to see if any coolant came out of the tranny cooler but non did.

Steveh29

If it wasn't leaking before installing the in-line cooler, then that would be my first suspect. Make sure all the lines are secure. Follow the lines to their termination points and make sure they didn't get tugged or bent and are now leaking. ATF is pretty thin so it could be leaking somewhere and you just not realize it. Maybe run the truck in park for a little while so the fluid lines are pressurized and see if you get a few drips on the ground.

I had a bizarre problem happen years ago with an automatic transmission on an old Ford. The vacuum modulator on the auto tranny got a small leak and allowed the engine to suck ATF through the modulator and into the engine where it was burned. Wasn't a large enough leak to make the engine smoke but it would drain the transmission after about a week of driving. I figured it out when I noticed there was an oily substance on the vacuum hose connected to the modulator. I wouldn't expect to see vacuum lines on a modern transmission. Just relating my basically useless story!

toyotaoffroad91

i smell a slight burning but i see on puddles or drips on the floor

khaug

Having seen the results of engine oil leaking into the coolant (common problem in older Porsche 944s), I think it'll be pretty obvious. The ATF and coolant won't mix, but will form a milky, oily emulsion. This should coat the inside of your radiator cap, coolant overflow/expansion tank(s), etc. Your coolant level should also be rising, if you've lost as much as a quart of ATF.

Regards

TechWrench

If your trans cooler in the radiator is leaking, you will see a milkshake like mix in the radiator. If that is the case, the radiator will have to be fixed or replaced real soon and the engine cooling system flushed.