so i am just gona keep the th350 and put 3.73's in but i have to fix the leak, which is pretty bad, but ican't tell where it is coming from. i know there is a seal in the front of the trans, is there one in the back where the driveshaft goes in? if so how do i go about replacing it?

 

it just pops outwith a lil prying and gently tap in new one with tiny bitofsealant around edge

there is also one one the gear selector shaft