Ok, so you might ask how did you not know. Well, I purchased the truck in March and have been concentrating on get it running right, good brakes, A/C, etc. The trans operated ok and only leaked slightly...so I did not pay much attention to it and assumed it was a TH350. Then, I drove the truck 350 miles in one day...mostly highway at 75mph indicated. Upon returning home, the leaking was worse and bad enough to warrant repair.
So, assuming a TH350 I purchased all external seals/gasket. I pulled the pan/filter and immediately thought to myself something seems odd. Sure enough, after a bit of online investigation, I discovered it is a TH700R4 (4L60). Dang or hurray, not sure which. I thought the TC cable was the TH350 kick down cable and always thought it odd that I did not have a vacuum line connected to the trans (i.e. modulator).
Anyway, the leaking issue is mostly from the pump to case seal (o-ring)
Obviously not an easy fix. So, I was thinking of trying one of those stop leak products for automatics...something I never have done or even recommend. What do you think, might it work? I fear the o-ring might be broken and the stop leak won't work. Dang!