I just installed a 01 transmission in my 96 max and it appeared to be driving fine until I realize it is not responding to the O/D button. If you press the
O/D button nothing happens and the transmission would not shift that final gear so I guess it is only running 3 gear what could that be? Help.......

 

The wireing is different on the 5th gens. Compare FSM diagrams.

I was told the connectors were different, I am surprised you even got it to work this much.

 

Where can I find the FSM diagram

 

www.phatg20.net

 

sell both of the trannys and swap a 5spd and never look back. trust me.