Transmission leak on 1995 gmc c1500 automatic
How do I replace a seal on the back end of the transmission
so where it will not leak out fluid when I drive?
Sounds like you need a new seal at the rear of the trans. You will need to remove the driveshaft to replace, pop out the old and hammer in the new.
Mark the driveshaft orientation before you remove it, and install in the same spot as before so as not to introduce vibrations and out of balance driveshaft.