Automatic transmission oil burning



The Ford Explorer making white smoke on long hill climbs (8/25/07) could be ingesting transmission fluid through a vaccuum shift control modulator with a broken diaphragm. I have had this occur on a on older Subaru.


I think they are right about the cooler line leak. That was actually my first thought when the caller mentioned the white smoke. I was however surprised that it took them so long to explain the smoke.

I had a cooler line leak in my car, and I had white smoke coming from ATF leaking and blowing back on my exhaust system. When your driving and see this in your mirror it could appear as if its coming from the tailpipe.


Something else that might be the cause of this problem. A small amount of water or coolant in the transmission oil when heated sufficiently will cause a massive foaming of the oil. I once tried to boil off some coolant contaminated oil so it could be disposed of. A 1/2 inch of oil in a pan foamed enough to overflow a 4 inch tall pan – x8 volume expansion. If this were to happen in a transmission the oil would exit via the vent on top of the transmission and some would most likely end up on the exhaust pipe and muffler. You easily could blow out three quarts. The situation would not recur until the transmission got that hot again. Also can you imagine what the froth would do if it was pumped into the torque converter and line pressure – more heat. The fact that fluid has not been lost since, points away from the cooler lines as pressure in the cooler lines goes down as the oil gets hotter because flow is on the down stream side of the torque converter – unless the cooler is plugged up.



Your theory is possible, but I dont think you can rule out the cooler line leak just because he is not loosing atf still.

We had the smoke happen a few times on our car before we found out it was the cooler lines.

This was on our around town car that seldom was taken on longer trips, but every time we drove it for a good two hours or so, the car started smoking and we lost fluid.

Between these incidents we drove the car for 6 months without any loss of fluid.

After the second incident we only drove the car around town until one day when I parked the car outside a store and suddenly white smoke was everywhere and I had a trail of leaking fluid after my car. When I popped the hood it was clear that one of my hoses had ripped open.

I then realized what probably had been happening is that the two rubber hoses had rubbed against each other, resulting in a small hole. This hole was probably so small that when the rubber and atf was colder it wouldnt leak, but when the car was driven for a few hours the heat probably caused the rubber to expand, and the atf to get thinner. The atf then dripped down on the protective metal plate under the engine and also blew back on the exhaust system.

I replaced both rubber hoses, and I felt so confident that this was the problem so next day I took the car for a 6 hour trip, longer than it had ever gone before… Since then Ive had no problems at all, and the car has been taken om more and longer trips than we would before when it would “overheat”.


This happened to me, and it was the head gasket in the engine.

Exhaust was getting in the coolant, and coolant was getting in the exhaust. The coolant in the exhaust made the white smoke. The exhaust in the coolant raised the temperature of the radiator to the point where the ATF burned. The head gasket, coolant, and ATF had to be changed out.