Mysterious transmission leak

[rwassom]

The other day I pulled up to the lights in my '63 hardtop and immediately noticed smoke coming from underneath the car. I pulled over and discovered a constant drip (a drip every three seconds) of transmission fluid from near the inspection plate. The car was flatbedded to a mates house who has a hoist. When we fired it up to move it into the shed and on the hoist the constant dripping had stopped.

Two hours checking the most obvious causes failed to find the leak. All the fittings are tight, the dipstick is firmly in place and it isn't coming out the vent tube. The entire transmission was degreased and the car run on the hoist for nearly twenty minutes with no leaking. A half hour run on the road had the same result, no leak.

I've driven the car very carefully several times since then and the leak only returns after a drive of about 45 minutes or more. Once the car has had time to cool the leak disappears.

I thought that it might be overheating and blew out the cooling lines but that hasn't fixed the problem.

I've pretty much run out of ideas and am hoping that someone out there might have some suggestions.

cheers,

[Ford blue blood]

Sounds like the front seal, why after hot don't know. Mine is the opposite, drips cold and stops when hot.

[sc4668]

I had the same problem with my 61 Tbird in August of 2009 while up in Reno at Hot August Nights. We had been crusing for a couple hours and were in traffic the car started smoking and smelled like trans fluid. I pulled of the road and looked under the car and trans fluid was running out right at the inspection plate. I let the car cool down then drove to Auto Zone and put trans fluide in. Drove the car back to the camp ground about 20 miles with no problem as this was Sat night and we were leaving in the morning just loaded the car and headed home. Took the car to my friend trans shop and explained the problem. The trans was pulled and resealed and an external cooler was installed between the radiator and the A/C condensor out of sight as this is an orginal car. Went to Reno the next year cruised and spent time in traffic with no problems. This was a good fix might help your problem.

[rwassom]

Thanks Ford Blue Blood and sc4668! I haven't had a chance to have an in depth look yet but will get around to it this winter (June, July and August down here in Tasmania). I took it out a couple of weeks ago and after an hours drive on a hot day it wasn't leaking. However, the leak had returned by the time I got back home. It can't be much though because the fluid level rarely drops and when it does it isn't very much. Go figure!

[dragonfyire]

i had an 86 thunderbird that had a similar issue but it wouldnt leak due to heat but when i hit 63 or faster i had just replaced the torque converter but didnt even think about the seal considering im not much of a mechanic and neither where my helpers but it dripped down onto the exhaust and would smoke like a spy hunter game. so therefore i would definatly have the seals done.

[Adrian]

I am have the same problem with transmission oil dripping on my garage floor when its not been driven for 2 or 3 weeks would it the torque converter draining back ?? and would it be ok to put Bar's Leak in the transmission oil ?
Cheers Adrian

[stubbie]

If you only drive your car about once every now and then the oil might be getting above the seals in the shift selector shaft. What happens and how it was explained to me, the transmission is sort of over filled. When driving the fluid stays at the top of the transmission. When stationary for long periods that oil drains down into the sump and rises above the shift shaft selector seals and eventually onto your garage floor. So best to keep it running at least once a week.

[Adrian]

THANKS Stabbie as I done drive it much I will try that and see how it go's
also it will boil if I idle it for 20 minute or more it has had a new radiator so if I put a electric fan in front of the radiator should that fix it cheers Adrian

[stubbie]

20 minutes is a long time for an engine to sit and idle. A fan would help, how much I don't really know.