HELP!! Major fluid loss question.
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Tuned
Joined: Feb 2003
Posts: 424
Likes: 4
HELP!! Major fluid loss question.
I've got a question about a gremlin affecting my C-5 transmission. It's in a Ford car, and I hope I don't get blasted for asking the question on the truck forum, but I've found this to be the best forum anywhere for getting good information from very helpful people. The question is also relevant for trucks because I'm right now considering a Ford Ranger with a C-5 in it.
The transmission has never caused trouble, still doesn't, does everything it is supposed to do. But, it is losing a tremendous amount of fluid, about a quart every 500 miles. The problem is that I cannot find any sign of where it is going. There is none in the radiator. The lines to the radiator are dry. The tranny pan is dry (I've replaced the gasket and retorqued bolts repeatedly). There is none dripping from the bellhousing. I've parked it on concrete and over cardboard looking for drips, and I get a drop or two that appears to be engine oil rather than tran fluid. Can anybody give me a clue as to where this fluid is going?
Thanks
The transmission has never caused trouble, still doesn't, does everything it is supposed to do. But, it is losing a tremendous amount of fluid, about a quart every 500 miles. The problem is that I cannot find any sign of where it is going. There is none in the radiator. The lines to the radiator are dry. The tranny pan is dry (I've replaced the gasket and retorqued bolts repeatedly). There is none dripping from the bellhousing. I've parked it on concrete and over cardboard looking for drips, and I get a drop or two that appears to be engine oil rather than tran fluid. Can anybody give me a clue as to where this fluid is going?
Thanks
Post Fiend
Joined: Jul 2006
Posts: 6,948
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Have never worked on a C5, but as I recall it replaced the C4 as a lock-up unit from 82 to 86, and was then replaced by the AOD. I do not recall if the C5 used a vacuum modulator or not, but your symptoms might indicate that the engine might be drawing a vacuum through a failed component, and burning your trans fluid through the tailpipe.The fluid has to be going somewhere, and if it is not on the ground, it might be being consumed at such a slow rate, that you barely notice the white smoke. I would check any vacuum lines to verify that they are dry inside. That amount of fluid will leave the inside wet, and easy to check.
Thread Starter
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Tuned
Joined: Feb 2003
Posts: 424
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Thanks for your quick replies. I think 75F350 is right on the money, although I won't know for sure until tomorrow when I'll jack it up and pull the vac modulator. I checked the mod. vacuum line at the vacuum tree, and it was soaked with oil and spongy.
If the vac. mod. is leaking, how come it wasn't affecting the shift points? The tranny has been operating fine.
Thanks again.
If the vac. mod. is leaking, how come it wasn't affecting the shift points? The tranny has been operating fine.
Thanks again.
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
I would imagine that if the hole is small enough it is still possible for the modulator to still function. That oil still takes up space, and could add just enough surface tension to leak, but still operate.
That was just a wild guess.
Glad to see that you may have found the problem, good job...
That was just a wild guess.
Glad to see that you may have found the problem, good job...
Thread Starter
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Tuned
Joined: Feb 2003
Posts: 424
Likes: 4
The problem was the vacuum modulator. After taking it off, I pulled a vacuum on it. It held for several seconds then there was a slight popping sound and it lost a couple of pounds, then another pop, more loss, down to about 5 pojnds of pressure before it stopped losing vac.
Again, thanks for your quick replies and good guesses.
Again, thanks for your quick replies and good guesses.
