If I put it in 4w hi the front drive shaft is engaged.With it in 2wd the shaft spins freely so I guess that means the transfer case vacum is working.But the 4wd is not working any ideas would be great.thanks in advance Danny.

 

I'm sorry Danny, but you have it backwards. If the t-case is engaging and the front axle isn't then you have a vacuum problem. Check under the battery tray with the engine running and t-case in 4HI to see if you have vacuum to the front axle actuator. If you do it's the actuator or the cable to the front axle. If you don't you either have a rotted or disconnected vacuum hose or the vacuum switch on top of the t-case is bad. Please post back after you check or fix it.