Hey there, crazy thing happened. Drove my truck about 35 miles. Stopped, the transmission emptied itself through the inspection plate on the front of the bell housing. Let her cool down, filled it back up and raced home. Again I parked and she dumped fluid. Filled it back up and it sat for a week... Since then I've taken about 10 trips, varying from 2 miles to 50 miles... Transmission no longer leaks! Any one have any ideas? Ive never seen a leak that will dump 4 quarts one day and then just stop!
oh and it's a 79 f150 with a 400 backed by a c6. Truck has a 6" lift and 35's not that I'd think that matters.... I've only owned it for a month. All I have been able to find is it used to be a manual transmission truck. But previous owner must have changed the radiator too, as the cooler lines for transmission are there and hooked up.

Side note. on day of leak, it was about 80 degrees. Recent trips have been 70 and belowScratching my head here...

 

The torque converter hub seal can get hot and leak. Once it cools it seals again. It can do this several times before it fails for good.

 

Thanks for the reply! I've never heard of a seal doing that, so good to know that info!
what do you think the chances are that the leak was related to the truck sitting for a year or better?

 

Maybe.....

 

Kind of like an old duraspark module, usually give you a couple warnings and the next time you are sol.

 

Is that separate from the torque converter seal at the front of the transmission pump ... behind the TC? I think mine did that once 7 or 8 years ago, it worried me some too, but after topping it off at home and putting a little Lucas seal juice in it, it never happened again and is dry in there when I look. Prior to that day, the truck had "sat unused some". It was a period after I retired and before I started part time at Advance when I rarely used it. I do drive or run it more since then, even took to driving it regularly to places, dumpsters, my PT job, etc.

 

That is another name for the same seal.

 

Thank You Sir!.
I just never had head it called a converter hub seal.

I first thought trans was shot. I eventuaslly came to think ithe seal had dried out some, maybe shrunk or hardened ... and the seal juice conditioned it, like softened it, swelled it ... as so far it's never done it again. I knew that day that it was red fluid running out onto exhaust cross over pipe just after starting & befiore it got hot even. I do make sure to drive it more often since.

 

Nice info guys! It's great to have a little insight on this!
if it got hot... Any thoughts on adding a secondary or a better primary transmission cooler? Would it help prevent this in the future? Or just a waste of money

 

It could be that the seal was just dried up & shrunken. Getting fluid all over it swelled it back up and made it seal again. But it should probably be replaced sooner rather than later. But it may not be worth the effort if this is only an occasional driver.

Trans coolers are great, but not always necessary. It is possible to run them too cool.

Get one of those cheap IR laser thermometers, see what temp the trans is running. Anything under 200 is fine. 180 is ideal.

 

I have a secondary cooler and mine wasn't even good warmed up when the event occured. I think mine had just sat unused for too long and the seal stiffened up, became less compliant to the TC surface maybe. I use it more regular, and that dose of Lucas didn't hurt it either. It has been fine ever since, that was a good 8 or 10 years ago. It has never left my mind, but Ive checked in the TC access plate, it is always dry. It was wet after the incident but I sprayed brake cleaner in there under the TC and then blew it out with air so I could detect further leaks. I really should change my pan gasket too as it leaks, I see the red drips under the bell housing, but then I check and it's dry inside ... so the drips are from the pan gasket running to the lowest point.

Having said all that, I do recall following a Dent pulling the grade on North Mountain on I-64 west of here, he was pulling a enclosed trailer. It's a good near straight 3+ mile pull with big curve at the top. It was a hot day, suddenly "big smoke" and a wet trail to his pulling over stop ... his C6 had puked. Tow truck driver was called, he loaded the Dent up on the rollback, hooked the trailer to his rollback's hitch, towed it all to Lexington. He told me later that after it cooled, he changed the fluid and it stopped leaking and the guy left headed to Kentucky, trailer in tow. All I know is he made it over North Mountain and out of the county..

 

I was discussing a similar event elsewhere on the internet.

It's common for the older transmissions to "puke" when they get hot. Towing (especially in hills), creates a lot more heat than just cruising. This can be concerning however, because trans fluid is pretty flammable. Usually there's no damage and all it takes is topping it off (or a filter/fluid change) and they're back going strong. Large coolers are a must when towing. And the factory style oil/water cooler in the bottom of the radiator is very effective. I always recommend using them. If there's a heat issue, adding a oil/air cooler post or prior to the radiator can address that.