Has anyone replaced the actuator on a mid to late 90's Chevy 1/2 ton pick-up. The light on the transfer case plate lights up in 4 hi and 4 low, the front driveshaft spins, but the front wheels do not move under power. I was told it is probably the actuator. I was wondering how hard it is to remove and replace and if that sounds like the correct thing that is wrong. Thanks in advance for any help.