My 78 Supercab has me wondering about the t-case shifter pattern. This is what's on the t-case shifter ****;

High Lock
High
Neutral
Low
Low Lock

If it matters, the truck also has a Dana60 up front.

 

Looks like full time 4wd. Possible NP 203?

 

Yep, sounds like full time 4x4. Check your front hubs and if there whether you have locking hubs or drive flanges with no lock-outs.

If there are lock-outs, it may have been converted to part-time 4x4 at one time. Only way to tell for sure is to look underneath and see whether you have the New Process 205 (gear drive, part time) or New Process 203 (chain drive, full time) transfer case.

 

If the transfer case is one solid piece its an NP205

If theres a range box bolted to the front of the transfer case its an NP203