I have a 2000 chevy silverado 4x4 1500 that shifts on the fly 4WD but when I put it in 4 low the front tires have no power. The transfer case goes into gear and the differential and drive line to the front wheels turn. What could it be?

How have you determined the front axle has “no power”?? And NO, you can’t shift from 2H to 4L “on the fly” without serious problems…

I know you can’t shift from 2H to 4low. How I determined is that I was sitting in sand and my back wheels were turning with it in 4low and I can tell the front wheels are not grabbing. i got out, had my wife push on the gas and I watched the drivline to the front wheels turning and I hear the transfer case going into gear

If the front drive-shaft was spinning in the sand pit, but the wheels were not turning, then the “automatic hubs” were not engaging, one of them at least…

so it could be the auto hubs r those easy to change iv only changed locking hubs

Obtain a service manual for your vehicle…There are many different types of “automatic” hubs.

Does the Silverado have the Controltrac or Autotrac setup? I have a 2000 Blazer with Autotrac. The front axles are engaged using a vacuum operated actuator. The actuator is underneath the battery tray. There is a switch that controls the vacuum to the actuator. This went bad on my Blazer. The switch is mounted to the firewall on the Autotrac system. On the Controltrac system the switch may be mounted on the transfer case.

The front axle can be engaged by disconnecting the vacuum line from either side of the switch and splicing them together. This is how I verified the switch on my Blazer was bad.

Also check all the vacuum lines, the ones on my Blazer were rotten in a few places.

Good luck,

Ed B.

Some 4wd systems do not fully engage unless rolling.