I have a 58 f100 with a 429 and c-6. the tranny is leaking up front at the convertor housing. When I just recently installed the motor and trans, I put in a new front trans seal, but I thought the wear line on the convertor would not be a problem because of the new seal. Can someone tell me if this wear on the convertor shaft is a common leak point. It does not seem to leak when running, but when just sitting it leaks terrible. I know I'll have to drop the trans to fix this, but I hope when I go through all this trouble, it will have been caused by the wear line on the convertor. Thanks::

 

There were a few years of the C6 behind the 429-460 engines that had problems leaking between the front pump and the housing when not running. I had this problem with my old F150 and think the trans was a '75 model. It would leak 2-3 qts. if the truck was parked nose down for a few days. There is a repair kit to fix this, but I'm not sure what it contains. A buddy of mine fixed mine for me.

 

If that is the situation (a kit) I think it would be worth your while to suck up to some ford tech and see if there is an old TSB (technical service bulletin) or what ever they called them in the dark ages, OR ....search the net until your fingers hurt.

 

My answer is long so forgive me...
Sometimes when you have a wear mark on a converter hub it can leak worse with a new seal. This is due to a couple things:
First the previous seal is what caused the wear in the first place. The seal and hub sort of wear in together gradually. Sometimes not leaking at all or just seeping.
Secondly, when you put a new seal in that seal is holding to its proper shape, sometimes not conforming to the wear mark in the same place,etc.
Third, there are small differences between seal manufacturers, meaning the "wiper" part of the seal that rides on the hub may not be in the exact same place or thickness. I usually hit the converter hub area with scotch brite for a few seconds, if it looks good or you can't feel it with your fingernail, it's generally ok.
I don't think this is your problem though. On automatic transmissions, the fluid is "overfilled" (according to the dipstick) untill the engine is started. At that point the pump sucks the fluid from the pan and into the various hydraulic passages, etc. So to put it simply the fluid level when not running is higher than when running. Usually, if you have a front seal problem bad enough to gush out when shut off it will leak when running as well.
The fluid is about an inch above the dipstick hole when the engine is shut off in most domestic automatics. Check the dipstck tube o-ring (common) and the pan, especially the front area.
If you still think it is coming from the frontal area, the pump gasket and/ or o-ring could be leaking. Also there is a small plug inside the bellhousing that secures the shaft for the intermediate band apply strut. They usually have rtv on them and are the right height for a leak when shut off. Also, make sure the seal is in very straight and not distorted or cocked. By the way, I am a Ford transmission man. Feel free to email me directly if you have more questions.

 

fiftysixfordf250 Thanks for the reply to my problem, it gives me a lot more to think about when I pull the tranny. I didn't know if when the motor wasn't running, the fluid in the torque convertor ran back into the pan and filling the transmission would make it leak from the front seal if the groove on the convertor was not sufficiently working.