The repair manual I bought.
I got more info on the transfer case from JPMagazine on-line. I learned that I don't need a special Jeep tool to determine when the chain from transmission to transfer case needs replacing. Drain case and open inspection port, push chain up with screwdriver, if it moves more than a half inch, replace.
I have bought several Haynes Repair Manuals, for Ranger pickups, for Escorts, for my F-150, for Dodge Shadow and one for Datsun 200SX. I also have other repair manuals, a Chilton for 1979 Plymouth Volaire (or as we call it, LT's revenge, I didn't know how much my father-in-law hated me until he gave me that car), one that covers cars from 1972 to 1979. A couple of Motors Repair Manuals, one covers cars from 1964 to 1970 and one that covers 1980 to 1986. Years ago I picked up a Jeep shop manual for Jeepster Commando at a yard sale.
I think what is frustrating me is my inability to find the info I need to fix the truck. I know I need to replace the chain, but I would like to know more about the inner workings of the transfer case. Also a vacuum line diagram for the transfer case controls would be nice.