So im finally taking out my TH350 to replace some seals and also doing the rear main seal. My question was whether or not i need to drain the transmission? i looked at a couple of guides and such and they dont seem to mention anything about it but i just wanna make sure. so im not running to the store last min. im just replacing the front pump seal and the tailshaft seal on the trans. I know i need oil for the rear main seal already.

 

When I dropped my 4 speed, I did not have to drain it. As long as I didn't tilt it too far back, it didnt drain. I kept mine on my tranny jack the entire time, too.