Re: Advice on some problems
First of all, congrats on your purchase!
Manuals, I recommend Haynes and the Factory Service Manuals. They are both invaluable. Chilton's isn't vehicle specific enough for Jeep work IMO. Haynes has a nice section on the shift linkage adjustment for the tranny and t-case.
To shift into 4wd. First of all, you should have a set of vacuum lines going to the front axle. The vacuum motor there is more than likely shot, but you might be able to use some WD-40 or other lube to free it up. That vacuum motor is what engages the front axle. If the front axle won't shift, the t-case won't shift into 4wd (and you don't want it to, as shifting into 4wd without the front axle would burn up the viscous coupling in the T-case). There is also a vacuum motor on the t-case itself. You should lube this also to make sure that it works smoothly. Then, shifting into 4wd is as easy as (with the motor running) switching the dashboard vacuum switch from 2wd to 4wd. You should hear a slight hiss that fades away quickly.
The easiest way to tell if you are in 4wd is to be on a patch of snow/ice/gravel/mud and have a helper watch to see if the front wheels turn. Otherwise, you can try shifting into low range (rolling 2-3mph with tranny in Nuetral) by pulling up on the low-range lever. The t-case won't shift into 4-lo unless it is in 4wd.
I hope that helps.
PS. Pop over to IFSJA.ORG, they have a fabulous message forum and tech section that is a huge help.
Phillip J. Van Why
1985 Jeep Grand Wagoneer