Any possibility it's simply overfull? Long story short, back when I bought my '82 and made the deal and drove it home, it had been sitting for several years with only a few short drives right before me buying it.. So needless to say I got several miles away from the guys house where I bought it and it started puking tranny fluid.. You could see it, smell it and it was blowing smoke to the point that my brother was following behind me and thought it had caught fire before I'd gotten it pulled off on a wide spot on the shoulder to investigate. Like oil slick under the truck leak. Thought from the heat and pressure it knocked a hole in a dry rotted trans cooler line and sent tranny oil spewing everywhere (best guess while laying on the side of the road) so we cut em both off to good rubber, re hose clamped them, and went on our way. couple miles down the road, same thing! Oil blowing everywhere, smoking and burning off the headers and exhaust making it look worse than it was! Got out and checked everything again, couldn't find a definitive source when stopped on the side of the road.. Took off again to more smoke and oil a mile or so later, My brother called asking if I wanted to abort and go get the trailer and come back for it, My response was "I'm not stopping at this point, we've got 10 more miles to go and it's either going to make it or grenade the sonofabitch!" I hung up the phone and kept driving, It carried on the whole rest of the way home, and even though it would very nicely BANG second and drive, it acted like it was half slipping at both part throttle and speed so I thought "If it makes it, it's probably Gonna need a trans rebuild".. Well, long story short, guy I bought it from had knocked the dipstick out, didn't get it seated all the way when he put it back in and overfilled the trans, by a lot! And basically, while I was driving home it was finding it's own level by puking out the excess from the vent tube! Once I got it home and cooled off to where I could crawl around and look at it, I could see the dipstick grommet was torn and the tube wasn't bolted up on the bellhousing. I'd guess he had about 3-4 quarts too much in it. But even after I made the repairs and cleaned it up, it still looked like it was leaking from about 3 other places for awhile after the fact.. And the slipping part of the trans, there's a difference between ported vacuum and manifold vacuum and that makes a huge difference for the modulator on the trans as to where it's hooked up, and apparently the previous guy didn't know that.. Lol switching the hose location solved that problem, and gave way to no slipping and happy, firm shifts! But I questioned it still for the next few months (mind you I only put about 500 miles on it last year) whether it was still leaking somewhere, because I'd drive it and it would leave drips, off the pan, off the rail, around the shift linkage seal, around the modulator, around the cooler lines and on the driveway.. basically anywhere tranny oil had penetrated from that vent blowout ordeal, it would leech out of when it got hot while driving, and it would make it look like a repeat or new leak.. Finally I said the heck with it and just drove it, and had fun with it, and after enough time and heat cycles, it doesn't "leak" anymore.. I know, long story, but I like stories, and I like trying to help..