Drain plug behind the torque tube?
 

There looks to be a drain plug directly behind the torque tube in the side of the gear box that I think is the transaxle oil drain. Can somebody please let me know if that's it or if it is something else? Also, where is the fill plug for this?

I'm thinking if it's the transaxle drain then the fill plug for the differential fills both but I'm really not sure.

Thanks!!

That's correct. Differential plug fills both. Both ends have their own drain plug even though almost all oil comes out from either one.