I have a 2000 gmc with the push button 4x4. It wasn't working, but no service 4x4 light and switch lights up like it should. I replaced the front actuator and while I had it on the lift engaged the 4x4 and the front spins, and won't when disengaged. Took it off the lift and tried it out and no pulling from the front tires. Light still works right and can hear it kicking in/out. Any pointers will be greatly appreciated! Thanks.