4WD front hubs locked?

jmrwiseguy · October 17, 2002

I've got a '01 Silverado Z71 that is acting like the front hubs are locked or engaged all the time. I notice it when I'm backing up and turning the wheel -- I can feel the tires grabbing in the turn. The 4WD seems to switch between Auto, 2WD and 4WD ok (no service light on either).

Any ideas?

Shaners · October 17, 2002

It sounds like something isn't quite right in the front differential.

If I understand the 4wd correctly on these trucks the front hubs are always locked and the disconnect for the front axles is in the front differential.

When you are in "autotrac" the front differential should be engaged but the transfer case is not unless rear wheel slip is detected. If you are in 2wd the front differential should be disengaged as well as the transfer case.

If you have warranty left on your truck, you may need to go see the dealer.

jmrwiseguy · October 17, 2002

The problem I'm describing happens when in 2WD (the light indicates this). It problably happens in Auto as well, but I haven't checked (I usually use 2WD all the time except in wet conditions when having 4WD lets me start without slipping). I really haven't used Auto much.

95 Silverado · October 19, 2002

when your truck is parked, reach underneath and try to spin the front drive shaft by hand, if everything is disengaged as it's supposed to be it should spin freely, if the front axle actuator or slide is stuck the drive shaft won't turn. Being electronically controlled this could check ok when parked, but have an electrical problem causing the wheels to lock when not needed.

jmrwiseguy · October 19, 2002

when your truck is parked, reach underneath and try to spin the front drive shaft by hand, if everything is disengaged as it's supposed to be it should spin freely, if the front axle actuator or slide is stuck the drive shaft won't turn. Being electronically controlled this could check ok when parked, but have an electrical problem causing the wheels to lock when not needed.

When parked and engine off, the drive shaft seems engaged (I can't turn it by hand). A friend of mine mentioned that the control mechanism up front sometimes sticks. He said you can pull it out and see if it frees up the driveshaft. Unfortunately he's not around to have him look at it. Do you know which side underneath this is at? If I can find it I can see if this helps. Does his suggestion sound reasonable?