You need to establish what trans you have before the question of who can supply parts can be answered.
Your truck would have the SM-420 4-speed as standard issue or it could have been ordered with a NP-435 4-speed.
The SM-420 has the PTO on the drivers side and has this shift pattern;
...1..3
R..2..4
The NP-435 has the PTO on the passenger side and has this shift pattern;
1..3
2..4..R
Mike B
