'91 4.0L auto

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i have a '91 ranger 4x4 with a 4.0L and auto trans. i recently pulled the trans to fix a leaking oil pan gasket and when i reinstalled it i did not like the converter back up properly which broke the pump gears in the trans. well out came the tranny again and a new pump was installed. once it was back together it worked just fine. i drove it around some here at home for very short distances and it had no issues so i trailered the truck back out to my in-laws farm (the truck is my hunting/farm truck). well i drove the truck around here and there for about half a day and midday i had stopped the truck, left it running and then i got out and noticed that it was pouring trans. fluid out of the bell housing. i just backed the truck up and loaded it back on the trailer so i could bring it home. i got it home and parked it since i was/am working on an early bronco project. well today i decided to add trans. fluid back to the ranger so i could be sure and let it leak so when i tore it down it would be wet. well i added fluid, drove it around, and now it will not leak. any ideas on why this is happening? is it a heat related issue? i have driven it enough to warm it up. any ideas or advice will be appreciated.

 

[high5]

well this afternoon i drove it more and then i parked it and let it idle. eventually it started leaking out of the bell housing. i guess the input seal is bad but i am surprised that it only leaks once it gets good and hot.