4x4 problems, need help!
 

hey yall, ive been having some 4x4 problems with my 98 gmc jimmy. after replacing the engine and hooking everything back up to the transmission ive been having a problem with the 4wd, i might have hooked up the vacume lines wrong but i have no idea, when im driving it will kick into 4wd and make a humming sound and as you slow down you can hear it make a noise like its trying to grab the gear or something then you start driving again and its fine for a while, could it be a acuator or lines hooked up wrong? can someone send me a diagram of the hook ups, i have 1 line that i couldnt find the hook up for from the plug that has the 3 hook ups on the top of the transfer case, please help!!

Some diagrams. The little black dot on the diagram of the switch represents the little plastic locator on the vacuum mechanism.

Also see this link for a couple more good diagrams: https://blazerforum.com/forum/2nd-ge...se-help-83921/