C4 leaks... inevitable?

SadbutTrue

Founding Member
May 1, 2002
2,390
4
49
Granada Hills, California
My C4 has leaked... for as long as I can remember. Long ago I seem to remember seeing a post about how C4s pretty much... leak. But assuming that these leaks can in fact me eliminated, or minimized, it'd probably be a good idea to try.

Any common areas that are especially prone to leaking that I should be sure to check out when I get under the car tomorrow?

Thanks
 
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my father in law owned my car since 1970. He told me that my trans leaked for as long as he could remember. After i restored it, it still leaked. It was leaking from the bottom of filler tube as it fits in to the trans. After trying different o-rings, it still leaked. So then i decided to get a new filler tube. Guess what, no leaks! Turns out my father in law replaced the tube many years ago with the wrong tube.

No leaks after that...so far.

good luck
mike
 
Most leaks come from the thin trans pan that doesn't seal very well, and leaks worse when over-tightened.
Aftermarket aluminum pans have a thick rail that seals flat and won't distort. Trick Flow makes a good one.
 
Only leak left on my car is the Tranny - been fighting it for 2 years. So small now I decided to just live with - I do have a filer tube I need to put on yet. Has a hat instead of O ring - we'll see.
 
My C4 leaks from the pan also. Tried different gaskets a couple of times but nothing seems to help. I have been thinnking of getting an aftermarket pan like some mentioned above. My car leaks bad and pretty much changes the fluid by itself over time.
 
Mine leaked at the pan - even with new aluminum pan. Ended up putting gasket selaer (Right Stuff) lihglty on each side. Pan is fine now but got a small leak I think near filler tube - hard to trace but coming from up top - could be vent also.
 
C4 Leaks

C4's almost never leak from the pan. Almost all leaks are above the pan, runs down and looks like pan leak. C4's are as leak free as any auto. Places to check, dipstick (2 types of seal & are not interchangeable, servo cover, band adjusting screw, (use new nut every time when adjusting, nut has seal) vent, front & rear seal. Also modulator can leak and the vaccum line sucks the oil to the engine burning it.
 
Everyone has mentioned the common leak spots so I'll do a litlle hijacking.:D 66bluepony mentioned the vent and I was wondering if anybody has tried putting a very small filter there to absorb fluids? I know this is a very small issue but I'm feeling anal retentive this evening.