Im just a newbie but ive had my 2GNT for 4 years and know a little bit about a few things that can go wrong.

A year ago I replaced my transmission because low fluid levels caused it to wear out the internals. Probably the dog teeth or the syncros. This caused the transmission to push out 3rd gear at RPM levels anywhere higher than 3500. I also got a very annoying whyning noise from the tranny probably from gears meshing while dry.

The tranny fluid leak came from the CV joint outputs. When you launch a 2GNT you sometimes get wheel hop and the CV joints moving so violently destroy the rubber seals on the differential outputs. YOu can tell this is happening to you because your undercarriage and the back of your engine block will be completely covered in tranny oil as well as your driveway. I periodically put gear oil back in the transmission but was not enough to save it. By the time I got around to replacing these rubber seals and put new oil back in it the damage was done. I didnt like the way it was shifting and it made grinding noises sometimes.

Luckily I have a family member that owns a junkyard and sold me a good tranny with 15,000 miles on it. i still have the old one in the back yard.