1989 F150 standard cab manual transmission 4 speed with OD 4x4 I am trying to figure out what transmission I have. Help please

 

What is the trans code on the drivers door pillar? If it has 5 forward ratios it should be a Mazda M5 which would be the original trans for the truck, but given it's age anything is possible. A ZF5 for a small block engine from an HD truck would swap in, the most obvious difference would be the granny 1st that the M5 doesn't have. There are also a couple older 4 sp gearboxes that could swap in.. some with and some without an OD ratio.

 

Trans code is M and it is a 4.9L Inline 6

 

Yeah that is the M5.

 

Thanks I appreciate it