4wd not wanting to lock front axle

[Snakehearts]

I have a 2000 Chevy 1500 and my front diff is not locking to make it go into 4wd I have already replaced the actuator but still does not work t-case works just fine the front axle just doesn’t want to lock 

[riverbanks]

Check for power at front pumpkin actuator

[davester]

This post assumes you have a regular 4wd setup, and not an autotrak setup, as I'm not familiar with exactly how the autotrak stuff works.

 

Did you test that the actuator went in/out as you shift between 2 and 4wd?  How do you know the transfer case is working fine?

 

If it doesn't, then the actuator is bad, or there's an electrical problem, or the sensor in the transfer case isn't working (basically, something "before" the front diff has failed, up to and including the actuator [as you might have got a dud]).

 

If it does go in and out, then another common point of failure is the engaging shaft (not the right term for it) or the axle shaft going to the passenger side of the diff).  Try shifting the system into 4wd, with the actuator reinstalled, then lift one of the front wheels off the ground.

 

If you can't spin the wheel, then 4wd is engaged and working

If you can spin the wheel, and the front driveshaft is spinning with the wheel (as in, you can't prevent the driveshaft from spinning while spinning the wheel), then something has failed in the transfer case (probably the chain, but could be other things).

If you can spin the wheel, and it spins while you prevent the front driveshaft from spinning, then something is wrong with the front diff.  Most likely, it's one of the two parts I mentioned earlier.  They aren't particularly expensive to replace, and you can do it yourself, if you have basic tools to get the diff out of the truck.