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Trany fluid in gas ... I remember

Hi guys. I remember back when I was younger … you know, dinosaurs and carburetors … we sometimes used trany fluid instead of carb cleaner to cut all the varnish and junk in the system. Sometime straight up like spraying carb cleaner in the carb … LOTS OF WHITE SMOKE! Sometimes, maybe once a year, mixed in with gas to clean out the fuel delivery system. For what it’s worth, it seemed to work … back then.

I would pour a pint of trans fluid in the full gas tank to prevent vapor lock. ( 80 Bronco 351m )

Hi Guys,
I thoroughly enjoy your show’s content, especially your quick-witted responses. I have 2 comments about this show. First, I had been advised to pour a quart of transmission fluid into my 100 gallon aux. diesel tank to use in my 2002 Ford 7.3 liter engine, because it was designed to run on a higher sulfur fuel than is available today. I’m interested in your opinion of that. Secondly, I can’t remember directions either, so I write them down as they are given to me. Then I read them back to the provider, to see if they are what he intended to give to me. Sometimes, the right turn becomes the other right (left). Guess some people don’t know the difference. Sometimes, I dictate the directions into a hand-held portable audio recorder.

back in the day my father poured tranny fluid in the carb. heused it to free up sticky valves and to lube the carb

ATF is a very good detergent and penetrant. If used to soak the combustion chamber it can loosen carbon deposits and stuck rings. But on modern cars its an O2 sensor and catalytic converter killer. Plain old blowby from oil rings is one of the major limiting factors controlling life of catalytic converters. And anything such as gas, oil, gaskets, or gasket sealers is specially formulated so as to be O2 sensor safe. ATF is not formulated to be O2 sensor safe. In early 1980’s when GM first started using silicone sealer without gasket for rocker arm covers they had premature O2 sensor failures until the silicone sealer was reformulated. Traces leached into the oil, traces of oil was burned in combustion chamber (even in new engines), and O2 sensors failed. Its that delicate. These days any reputable automotive silicone sealer will be labeled, “O2 sensor safe.”

Another example is with dirtbikes which many are now fitted with O2 sensors. In the past it was not uncommon to put premix in 4-strokes so as to be prepared to help gas guzzler 2-strokes out of the woods when/if they run out of gas. Or to use premix from a 2-stroke to help a 4-stroke out. Was quickly found that less than a gallon of 60:1 premix would kill a 4-stroke’s O2 sensor. On the radio show 1 quart of ATF to 20 gallons was discussed at 80:1 which is leaner than 60:1 but enough to concern me.

papappy, unlike others you do have a valid concern. Higher-sulfur diesel provides lubrication for the fuel system which is lacking in ULSD. With the high pressures involved there is plenty of opportunity for wear. There are aftermarket lubricants designed specifically to replace the missing lubrication, 2-stroke oil is not the best but its generally better than nothing and cheap. Spend some time with Google as there are industry accepted test procedures for diesel fuel system lubrication and more than one published test results of many different additives toward that goal. Don’t think a quart in 100 gallons is going to do you much good.