1988 2.9 automatic problems

[88danger-ranger]

Hey guys, I could really use some help, this truck has me stumped. I recently got a 1988 ranger with a 2.9 and an automatic transmission. the previous owner had replaced the front seal in the transmission about a month before I got it and within a week of me driving the truck atf started pouring from the bellhousing. I got the truck hauled home and dropped the trans, and well... the seal looked to be in good condition but it was leaking horribly so I went ahead and put the new one in, put everything back together and within 50 miles it started pouring atf out again. I had this same problem out of an 86 b2 I had a few years ago and never found the fix. I had been told the breather line on top of the trans may have been plugged off and causing it to pressure up and blow the seal but I checked that line on this truck and it seemed to be clear. what I do know is the trans cooler has been bypassed so maybe its getting too hot? that and something else is wrong with the trans because it wont shift up right... I have to rev the motor up to like 5k then let off the fuel and it will upshift, maybe that is causing extra pressure? if so, what could cause the shifting problem? im pretty lost when it comes to transmissions honestly... any help is appreciated, im just tired of fighting with the junk.