I was wondering what might be causing my '03 to come in and out of 4wd, it's a push button system (2wd, 4HI, 4LO). When I plug my PPE tuner in, that's the only time a see a message on the instrument panel indicating any problems with the 4wd system "service 4wd". Other than that, no warnings that my truck is in 2wd when it should be in 4wd. By alternating between 2 and 4wd, most often I can get the 4wd to re-engage.

New transfer case, problem solved. keep an close on your transfer case for any signs of leakage.

thats a pretty lame response its kinda like saying i have a glow plug problem put a new motor in problem solved. a qualified shop could of rebuilt your t case for alot cheeper than a new one. if thats what you needed. im going to rebuild mine myself. its a tcase there is not much to it what did you do with your old one .