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Discussion Starter · #1 ·
Well, still on the quest to figure out why the pan gasket fails to hold the fluid in. On about attempt #12 and counting.../forums/images/icons/frown.gif /forums/images/icons/frown.gif /forums/images/icons/frown.gif Gave another try a test today, and didn't last much past the initial startup. However, the past 2 leaks that I have sprung are in a different location then that previous ones, so I am thinking that the case is in decent shape at least. I checked the cooler lines to make sure that the fluid was flowing properly through them, and it was, so the problem isn't there. Took the vavle body off as well so I could get a look (limited) at the inside of the tranny and nothing seemed to be holding up the fluid flow. The front band seemed loose, so I may have to check that again. How movable should the front band be by hand?? The rear band seemed to be ok, although I have been finding pieces from it in the trans pan. An interesting thing that I did not remember from the rebuild part is that I can rotate the planetary assemblies by hand in the counterclockwise direction (facing front of tranny). Is this normal, or has something broken?? There seems to be a little bit of play inbetween the planetary assemblies, so I assume that the clutch packs may be wearing down. The transmission shift quality is still pretty good, although it has degraded a little bit recently. Anyways, the just of the inspection is that I still cannot find any cause of the fluid leak. Midlife?? suggested that a valve in the torque converter may be malfunctioning, causing the fluid level to be high, but I have not heard anything about this before. Anyone else know about that?? Any other thoughts, or tests I should perform before I put the pan back on for another try.?? I am going tomorrow to get a C4 manual per previous suggestion by camachinist, but I wonder if even that will have a solution to the problem.

Anyways, thanks for any help.

Dave
 

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First, narrow down where the fluid is leaking from...since the pan gasket is about the lowest thing on the trans, fluid can be leaking from lots of places and end up down there...
FWIW, I've never had a trans pan leak ever...at the most just a light coating of oil after many thousands of miles.

The converter anti-drainback valve you speak of is in the front pump casting and can only be accessed when the trans is apart and even then it's difficult.

If you're getting pieces of the band in the pan (and you're sure it's the band), you've got problems. The bands should be a bit loose since the drums have to easily rotate inside them when not applied. There is a precise technique for adjusting them that should be followed to the letter...it's in most service manuals and I've posted it a number of times here..

It's normal to be able to turn the plantaries with the input shaft, with varying degrees of difficulty. You shouldn't have much thrust clearance in the stack but I don't recall the precise spec....maybe .032" or something like that. There's also a clearance spec for the clutch paks but it's been a long day *G*...depends on the number of plates..

Get the car up on stands and clean everything off good and start fresh with lots of light, that service manual and a methodical attitude. Post if you find anything weird or if you have questions. You'll get it yet...*G*

Good luck!
 

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Discussion Starter · #3 ·
I have been entirely open to the fact that the fluid may not be coming out of the pan, but I have jacked up the car numerous times, fired over the engine, and watched the fluid drip inbetween the gasket and the pan, on 3 different pans, and in 3 different places. The fact that it will seal for the most part until it gets reved up is what I can't figure out. I seemed to remember putting a small iron plug type thing in one of the orofices of the front pump per instructions with my initial shift kit, but it has been a long time and I don't remember what the purpose of that was. I am pretty sure it was pieces of the band that I found inside the pan, specifically the rear band, as there were little black pieces of kevlar lying in there, and I don't believe any of the other parts of the transmission use that type of material. I have not found any in the last couple times I have changed the pan gasket out. I found most of the pieces in the two times after I had the lockdown problem you helped me solve. I will readjust the front band and check on everything else, road test and see what I can come up with.

One strange thing I did note, was that there was a white colored deposit on the topside of the valve body, and I have no idea where it could have come from.

Thanks Pat
Dave
 

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Hi Dave,
Sorry I forgot that I had worked this problem in the past...it's been extremely busy in the shop lately..

Have you checked the case pan surface carefully for defects and straightness? This usually isn't a problem but your experience here is definitely unique, IME.....I know you've been using standard practices for pan installation (lots of experience, eh? *G*), so I'm a bit befuddled at the results...I can't believe 3 pans could be screwed up. Are you using the standard cork gasket? Given the leaks appeared in 3 different places, I'd discount the case but it's worth looking at anyway...could you map, either with a sketch or by description, where the leaks appeared? Use hard part references on the case if possible.

As that rear band is a big one, if you don't notice any problems with the drum (scoring, etc), I'd cautiously recommend continued use and monitoring, especially when engaging manual low or reverse. If you can get this leak problem solved, I'd recommend running the trans for 5K or so and then pulling the pan for a read and filter change...all this work can't be doing the cleanliness inside any good so that check and its findings would be a good indicator as to whether everything will be good for the long haul.

I don't know what that deposit is....did it come off easily or ? Has any moisture gotten in there recently, as in washing the engine off or anything (dipstick tube *G*)...?

Sorry I can't be of further help..it sounds like you're doing all the right things
 

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Discussion Starter · #5 ·
Pat--

I am providing a link to some pictures of the differences in the gaskets I have previously described, with sequential numbering of where the leaks showed up. The original pan is shaped like the black gasket on the left, without indentations, while the aftermarket one I recently bought is shaped like the cork gasket on the right with the indentations. Aside from the very first time, all the leaks have been centered around these indentations, and the first leak I am discarding as caused by the original pan as it was in pretty bad shape. You wouldn't believe how many times I got the "you must be crazy" look when I asked if they had an actual C4 gasket, and not a C5 type (indentations). Some of the parts stores books even had pictures showing the original 66 C4 gasket to be the ones with indentations. Since I had discarded the original pan, I could not use it as a point of reference, and started wondering if I had gone crazy..../forums/images/icons/smile.gif However, today I tracked down one of the non-indented C4 gaskets and installed it, and up to now, have had no leak. I will get after it good tonite and see what happens there. To answer your question, I have used cork, rubber, and neoprene gaskets, both with and without sealants to try and seal the pan. The current one is the black neoprene one you see in the photo. The rear drum looks to be in pretty good shape still, so I will continue using it and see what happens. The front band was a little loose, as after I readjusted it, it returned to about where I remembered it being. Any reason why that would loosen up?? The deposit did wipe off pretty easily, but I am still not sure what it was or where it came from, only thing I can think of is some of the sealants I have tried on the pan, but I don't remember getting those on the valve body.

Here is the link:

http://photos.yahoo.com/bc/davz289/lst?.dir=/Mustang

Hopefully it works.

Thanks
Dave
 

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Discussion Starter · #6 ·
Pat--

I forgot to mention on the pictures the right sides of the gaskets got cut off slightly because they didn't quite fit inside my scanner, but they are identical on that side. So if it looks a little funny to you, that is probably why.

Dave
 

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Thanks Dave for the explanations...it appears as if things have settled down for now so I'd say run it awhile and keep tabs on it....check your hot running and cold non-running levels and note the differences and see if they remain constant over time...also monitor the color and smell of the fluid and your impressions of shift quality both cold and hot...
If you didn't install a new nut on the band adjuster, that could explain it backing off...sometimes the old ones just don't cinch up right. Or, just like I've done many times (not on C4's *G*), you could have missed that torque setting somehow...I'm not pointing fingers..hehehe

You know I've found something in my years of mechanicing which is often true....Sometimes things are cranky until you leave them alone for awhile..*G*
 
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