It would seem that the transfer case must have been located remotely from the transmission. If there is enough space in the frame, the transfer case could be moved rearward, and an auxiliary overdrive unit such as a Laycock from Gear Vendors be placed between the transmission and the transfer case.
Alternatively, both differentials can be re-geared to a taller ratio; perhaps in the 3.00 to 3.30 range.

Off the immediate subject, Army mentioned "722.2 (if you can find one!)". I have a freshly rebuilt 722.2 looking for a home. No. Calif.