Can anyone tell me were to find good manauls for new process 203 and other transfer cases. Looking to rebuild a 203 Thanks in advance

 

The factory Chassis service manual for 1978 has a great section on rebuilding both the NP203 and NP205, both of which were offered that year.
I'm using it to go through the '78 NP435/205 combo that's going in my '91 during Christmas holiday (I hope).
Eddie

 

Another resource would be the nearest big library. I know the big one in downtown Houston has lots of rare factory service manuals.
Find one that has the pages you need and photocopy them.
Also, in the back advertising section of "Four Wheel and Offroad" and/or "Four Wheeler" magazines I know I've seen ads for a company doing "Rebuild it Yourself" videos, and I think they did one on the NP 205. Give 'em a call and see if they're doing the 203.
Last resort, just remember that a 203 is a 203 internally, be it Ford, Dodge, or GM.
Eddie