1992 Explorer automatic transmission leaks when under heavy load

[KeithOfOhio]

At 90K, the prior owner reported replacing the automatic transmission on this 1992 4L automatic transmission Ford Explorer 2WD/4WD and low-range buttons. Its now 50K later and used as a backup vehicle, when a 4WD is needed, and for putting/pulling a fishing boat in/out best done with an automatic transmission.

Started noting a small trail of ATF when climbing a 1/4 mile 22% grade hardtop access road to my neighborhood. It would come and go usually only loosing a few cups when it happened. However, the problem was more frequent when towing a small loaded 1200pd trailer or a loaded trunk up that hill.

My 2L hatchback car would not start and so I towed it 60 miles without any Explorer leaks or problems. But that 22% grade by itself experienced a TWO GALLON loss of ATF. The steep road got a foot wide oil strip starting 1/4 of the way up this 1/4 mile stretch. I had started carrying a case of ATF just in case. Me happy as I was able to dump in ATF while stopped on that hill allowing me to reach home.

Back home, I added another half-gallon to top off the ATF. I drove it back down and up that hill with no towing and there was no leaking. My engine oil level is okay. Four years ago, I had my first occasion to tow that car home and did not experience this massive leak.

Figure I have some seal that is failing and especially unable to hold back the ATF when the automatic transmission has a heavy load. Load equals pressure which at times is exceeding a seal's ability. I have no experience with automatics while have experience taking car engines apart and doing most other car repairs. I searched this forum and did not find any related posts to my surprise.

What am I looking at?
What seal is failing?
How difficult is it to reach and replace?
While in the process, are there other fixes I should do?

 

[BrooklynBay]

This is a common issue with the front seal blowing out in the bellhousing. Check the coolant level in the radiator. Never tow in over drive. You might have to drill the weep hole in the bellhousing to make it larger. This is the drain back hole for the torque converter. The front bushing in the bellhousing might have to be replaced. Replace the front seal in the bellhousing.