Technical technical

I have 1941 ford P/U with 70s-80s 350 and mid 70s th350 my question is when the truck sets for any length of time, like now that its winter the trans leaks a pretty good size puddle of trans fluid . if I drive it frequently does not seem to happen any of trans experts have any thoughts on any advice greatly appreciated thanxs in advance tom

 

the torque converter drains back, and it leaks out whatever seal is next highest up from the normal fluid level. Could be lots of things....speedometer gear seal, kickdown cable or seal, shifter shaft seal, accumulator cover seal, governor cover seal, rear yoke seal, front pump O ring or gasket or bolt gasket, etc.

you gotta clean it off, and then let it leak, and see where it's coming from.

 

I had that problem, along with many, and it was the dipstick tube seal/plug. If it moves around from not being bolted down it screws up the seal. Also cheep seal/plugs shrink and leak,,,

 

oops I forgot to mention the dipstick tube! good catch

 

thank you for the quick responses I thought it was something along those lines looks like I got the first project for spring

 

As per Squirrel's note there are lots of possibilities. I can't remember the last 350 or 400 that didn't leak when it sat during the Winter but the one leak that I have encountered the most is the Speedo gear. It tends to eventually wear in an egg shape pattern and, as such, it's damn near impossible to stop completely.

 

for the speedo gear, you can buy a new gear, and a new sleeve, and new O ring, and it might or might not help.

 

My 39 Ford 327 engine 350 trans combo leaks at least a litre of trans fluid over the winter. I added some LUCAS transmission fix and it did help some. It still leaks but not as much, I think they all do it.

 

I'm not a trans expert, but just a thought if you are interested.....
Could it be that when it sits for a long period, that the seals harden/contract and leak.
When you use it, the oil softens the seals and they expand and don't leak as much.

 

No.... It's as squirrel said...... The fluid in the torque converter drains back when sitting for sometime. A bunch of threads on here regarding the TH350.

 

TH 350's and 400's will leak past the convertor seal after sitting if the seal is old and not as pliable as when new. You crank it and drive it and get it hot and it stops leaking.
As crazy as it sounds a capful of brake fluid in the trans softens and swells the seals. That's an old used car lot trick to get leaky or even lazy transmissions to act right.
Did it to my P30 Chevy van to stop a front pump seal leak until the racing season was over. Two years later ,no leak and didn't have to pull the tranny. Still towed the round track car and trailer just fine.