heavy white exhaust smoke possible transmission vacuum issue?

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New member
Jun 17, 2013
I have a 1992 Fleetwood Coronado Class A motor home Ford Chassis which has been running well. Suddenly I started seeing white smoke billowing
from the exhaust. It smells and feels like it maybe transmission fluid. I have been told this maybe a vacuum issue forcing transmission fluid
into the exhaust system. There maybe a line or a valve issue, I do not know. Any thoughts?
Thanks, Wayne
Are you losing transmission oil? There is no connection between the EXHAUST systen and the transmission. It could be the diaphram in the vacuum valve that controls downshifting. This would allow fluid to be sucked into the intake manifold and then burned.
If you have a Ford F53 chassis and not a Oshkosh chassis, then your transmission is an entirely electronic E4OD and does NOT have a vacuum connection to the engine. Look else where for your problem. If you have an Oshkosh chassis with 460 engine, then you have a C6 transmission an DO have a vacuum modulator, that could allow transmission fluid to enter the intake manifold.

Thanks for the clarification, Richard.

Wayne, if it is the C6 transmission, pull the tube between the intake manifold and the modulator valve off and see if there is any fluid in it. It should be dry.
Smell the smoke. Most if not all antifreeze will have a sort of sweet smell. If you've ever had a coolant leak you know the smell. Tranny fluid smells like burning oil.


Just a thought. Are you sure the smoke is coming from the tail pipe and not just rolling out from underneath?
Thanks everyone for their comments. It is looking like I do have the C-6 transmission and the vacuum solenoid needs replacing as well as vacuum lines. The white smoke most definitely comes out of the dual exhaust and has a smell of fried oil. I just have to make time to get under the unit and check everything out. I hear that this is a common problem. I will let you know what the solution is. Hopefully not a tow.

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