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Chevy P30 box van 454 defying physics and logic

markvii1markvii1 Member Posts: 3
edited July 2015 in Chevrolet
I want to preface this topic by saying that I did not add transmission fluid into anywhere on my box van except the transmission, which is filled via the dipstick tube located under the engine cover inside of the truck on the back of the engine, nowhere near the engine oil dipstick or filler tube.

Now with that out of the way, I will explain what is happening to the best of my knowledge and will welcome any insights that do not start with "ARE YOU REALLY REALLY SURE YOU DIDN'T POUR THE RED FLUID INTO THE HOLE YOU PUT THE YELLOW/GOLD FLUID IN?" (because I did not)

Anywho, the van in question is a 1992 Chevrolet P30 box van with a GM 454 topped by a thirsty quadrajet carburetor backed up to a three speed automatic. It is used as a delivery van for an outdoor equipment rental service run on a resort island in the Southeast.

It likes to blow smoke from the passenger side exhaust pipe (dual exhaust, no crossover between sides) due to what I am assuming is a dearly needed cylinder head rebuild. While this is not unusual, what is happening underneath all of this is.

Recently the van has started mixing transmission fluid into the oil reservoir all on its own and smoking out of the passenger side exhaust pipe so badly it makes pedestrians choke and look at me like I blew cigarette smoke in their face. The transmission leaks so badly that I have to fill it with anywhere from three quarts to a gallon of ATF every week to two weeks. When I check the dipstick for the oil reservoir it shows that there is an oily mixture well over two inches higher on the dipstick than the fill line and the I changed the oil in it only two weeks ago (to the fill line) (with ONLY motor oil).

I guess the real question is why is my van trying to get mixology certification in its downtime and is there anything that can be done other than a full rebuild and replacement of the front two thirds of the drivetrain?

I love this van and it really helps to give our business some presence on the island. However I am certain it will fail spectacularly soon but I have no real clue as to where to even begin to rebuild it.

Thank you very much for reading and any insights into this puzzler will be greatly appreciated.


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    Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    edited July 2015
    If your transmission has a vacuum modulator valve attached to the outside, that's your answer. It's gone south and vacuum is sucking trans fluid into the crankcase.
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    markvii1markvii1 Member Posts: 3
    Thank you very much I will have to look into that in the morning when I am back at the office and will reply back with the verdict.
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    markvii1markvii1 Member Posts: 3
    You were right! Thank you very much for your insight the truck is running like it only has 85,000 miles on the clock. 
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