bartamos,

I do not understand your reply/post:
"If the fill pipe plug leaks, the drain plug would leak. Same threads, same plug."

The drain plug is on the bottom?
The fill plug is high up on passenger side?

The plugs themselves might be the same, but, the two plugs might not be leaking at the time.

Also: another filling topic: if you have an enclosed drive shaft, when you fill an emptied transmission or u-joint housing the gear oil levels out with the u-joint housing. It is a good idea to recheck a transmission oil-level after driving it, and after letting the gear oil "settle down".

Last edited by tclederman; 04/26/2018 7:08 PM. Reason: added "another filling topic"