So i engage my four wheel drive i feel it engage but the front tires wont spin.
the front drive shaft spins but the tires wont, what could be wrong, the vacuum seal was torn off but i had the shop put it back on, it hasn't worked since i got the truck i think. What could be wrong

 

How did you test the front drive shaft for turning? Lift and support the front wheels off of the ground and with 4x4 engaged and the tranny in Park try turning the front drive shaft. It should not turn. If it does the IWE are not engaging properly. Their default is engaged and vacuum keeps them disengaged for 4x2 action.

regards

Jean Marc Chartier