[Irelands child]

I'm having a brain f#$@ today!!!

I've had a fair number of these C4 transmissions apart plus installed a few cars. I currently have a modified unit in my '31 which has served me well except for a persistent leak from somewhere, but that's not my question.

The gasket, and this one is a cork, is oozing. I pulled the dipstick and it shows 4-1/4 inches above the full mark. Now, this car hasn't been started since late Nov. so I would expect some drain down of the innards, including possibly the torque converter - but this seems excessive in comparison with others I've had. This almost makes me wonder if I over filled it when I changed pans to add the temp gauge sender. I have never seen two capacity charts for these the same, so usually will fill it according to the dipstick - which I most likely did this time. As I can't start the car for another couple of weeks, and am going to install another pan (aluminum) will dump and strain the oil and refill. Any comments on this supposed problem?

There is no blow out of the dip stick or vent, nor any temp spikes - and does shift correctly.

(then maybe that's why I have that persistent leak )

Dave W

[1957plymouthhemi]

Hi Dave. I'm not sure I would worry too much about the overfull level on the dipstick until you can start the car. The convertor holds 4 to 6 quarts by itself and after 7 months of sitting has probably drained back at least half of that.

If you last filled it by the dip stick it's probably where it neeeds to be. On a side note, I'm not sure if you are aware of it or not, but there are 2 basic styles of C4; the small case, which can be identified by the dip stick tube going into the transmission housing and the large case which has the dipstick tube going into the transmission pan. The large case uses a larger convertor and has a larger fluid capacity. Also when I pull the pan on bigger transmissions (TH400s, 727s, etc) they usually take 4 quarts to top them back up, a small case C4 usually only loses about 2 1/2 quarts.

As far as the leak, I just got thru fighting one on a customers C4. I usually don't have too much trouble locating and repairing leaks, but this one was a real pain. I checked the usual suspects; manual shaft seal, pan gasket, and modulator. It was dripping off the left rear corner of the trans pan, but it turned out the leak was caused by the fill tube O ring on the right front corner of the pan. Because of the way the car was parked the fluid was seeping out dropping down to the gasket/pan rail and then flowing to the left rear corner before droping off.

[Irelands child]

Originally Posted by 1957plymouthhemi

Hi Dave. I'm not sure I would worry too much about the overfull level on the dipstick until you can start the car. The convertor holds 4 to 6 quarts by itself and after 7 months of sitting has probably drained back at least half of that.

If you last filled it by the dip stick it's probably where it neeeds to be. On a side note, I'm not sure if you are aware of it or not, but there are 2 basic styles of C4; the small case, which can be identified by the dip stick tube going into the transmission housing and the large case which has the dipstick tube going into the transmission pan. The large case uses a larger convertor and has a larger fluid capacity. Also when I pull the pan on bigger transmissions (TH400s, 727s, etc) they usually take 4 quarts to top them back up, a small case C4 usually only loses about 2 1/2 quarts.

As far as the leak, I just got thru fighting one on a customers C4. I usually don't have too much trouble locating and repairing leaks, but this one was a real pain. I checked the usual suspects; manual shaft seal, pan gasket, and modulator. It was dripping off the left rear corner of the trans pan, but it turned out the leak was caused by the fill tube O ring on the right front corner of the pan. Because of the way the car was parked the fluid was seeping out dropping down to the gasket/pan rail and then flowing to the left rear corner before dropping off.

It sounds ike you have gone through some of the same with C4's as I have. I've been fighting the drip for about 2-1/2 years. The kick down/shifter shaft seal is dry (that's unusual) the modulator is dry, there is a wee bit of dampness around the two adjuster nuts, but it's only a very small amount. The case fill dipstick tube did drool, but is now dry with the Hughes that uses the GM style of seal, the regular pan bolts leaked, but they were replaced with flanged bolts and sealing washers, the servo cover is a billet aluminum piece and is dry. Then there is that very narrow pan rail section that often leaks and thats totally dry.

Yep, I do know about the pan vs case fill versions. Internally, most I6 and V8 versions are virtually identical, usually just gaskets and modulators. It's only when you get to one of the 6 (at least!!) bell housings that you really start down the road to confusion.

I guess I'll just leave a bucket with some newspaper under it for any drips, change the pan and gasket then refill and hope for the best. Then, if I really get desperate, I do have a spare C4 all nicely rebuilt, modified with the good clutches and band, etc ....... but it is a royal pain working while lying on my back plus all of the claptrap that needs to be removed to get to it but it might just happen.

Thanks for the response

Dave W

[Irelands child]

I finally got to the transmission today. It had really leaked in the last week or so!!! And surprisingly, the pan gasket seems to have been the biggest culprit - but not just because of the gasket. The @#$% pan, a chrome aftermarket POS from Summit was so flimsy that torquing the bolts to my usual 12 lb ft (12-16 is spec), every bolt hole was distorted with visible signs of leakage between several bolts. I reinstalled my Trick Flow cast aluminum pan. I just wish I had used the rubber and steel gasket that Moroso sells - but too late for it this time .

[mmerlinn]

Originally Posted by Irelands child

It's only when you get to one of the 6 (at least!!) bell housings that you really start down the road to confusion.

I know of 32 different C4 bell housings that were sold in the U.S. by Ford and 1 more sold only in Oz. If you think only 6 will produce confusion, try 33!!!

[anglia427]

the band adjuster lock nuts are a common leak on that trans ,they have rubber seals molded to them and need to be replaced during a overhaul or after adjusting bands