Cloud of smoke from transmission


#1

In the show the guy was pulling a trailer up a long grade and saw a cloud of white smoke behind him. He stopped and found he was low on tranny fluid, he refilled it and said that since then it has been ok and he has not had to add fluid again. Click and Clack said he had a trans cooler line leaking. I don’t agree. What I believe happened is while towing up the long grade his transmission got hot and burped a slug of transmission fluid up the dipstick tube all over the hot manifold creating the cloud of smoke. I first heard of this happening while attending the Reese Hitch School, and then it happened to my dad while towing a trailer to Florida. Almost the exact same circumstances as the guy on the show. He called me to see if I had an idea what it was or if he needed to find a tranny shop. I remembered what the instructor had told us and told my dad to keep the rpm’s up to keep the tranny cool and just watch it. He never had any other problem and we never found any other leak from the tranny lines. While this guy may have a tranny line leak because his tranny was very low the cloud of smoke probably came from a burp up the dipstick tube.


#2

Years ago, I’ve also experienced this, where the transmission fluid due to trailer pulling gets too hot and spills on the exhaust manifold, creating a lot of smoke. For me it happened w/a 1956 Chrysler sedan pulling a house trailer up a steep hill. Such a thing may not happen with newer cars.


#3

I have never experienced “burped up a slug of transmission fluid up the dipstick tube” and I have gotten several transmissions really hot due to slippage; driving an RV up the Grapevine; and pulling a trailer in the Sequoias.

The only time I have seen oil expand excessively is when it has been mixed with water. I once tried to evaporate water out of coolant contaminated oil. A 1/4 cup of mixture expanded to a volume of about 5 cups. In WWII one way to sabotage a radial engine was to put a cup of water into the oil tank. When the engine got hot enough, the oil flashes to foam and exits through the vent system starving the engine of oil.

I am wondering if the above examples of transmission fluid loss is due to accumulated water. How could water get into a transmission? Possible ways are sabotage, a leaking transmission oil cooler, filling with the wrong fluid (water based), submersion by flooding, or driving through deep water. But I was wondering if the constant breathing of the transmission in cool moist conditions might condense enough water inside the transmission to produce the contamination i.e. short drive cycles in a humid enviornment. However, I have been inside a lot of transmissions and have never seen rust on anything. I was thinking that an oil analysis of high mileage transmission fluid might demonstrate the presence and quantity of h2o in suspension.

Has anyone else seen research on this subject or had any related experience.

Curiosity keeps me awake at night.


#4

Similar thing happened to me. The automatic tranny on this era of Ford has a ‘vacuum modulator’ that screws into the side of the tranny and attaches to a vacuum line. There is a diaphram inside the modulator that can rupture or leak, and when it does, the vacuum line then sucks transmission fluid into the engine, creating an epic cloud of white smoke; if you drove off a cliff, you could do skywriting on the way down!
It’s easy to fix. The aftermarket part is $30-40. Just screw the old one out and the new one in, attach vacuum line.


#5

The vacuum modulator in the transmission can fail allowing tranny fluid to travel up into intake manifold and create a huge cloud of smoke in the exhaust. I remember hearing about this years ago.


#6

It can come out of the dip stick. This why on GM trucks the trans dip stick has a fip lock on it now.