Question about GMC Cars & Trucks
I think you have a separate actuator on the front diff which operates off vacuum. The vacuum can is under the battery tray and any lines leaking can cause this issue.
Posted on May 05, 2015
a 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of.(from cars to computers, handyman, and even drones)
click here to download the app (for users in the US for now) and get all the help you need.
Posted on Jan 02, 2017
SOURCE: four wheel won't engage
Theres a vacume dash pot under the battery box. It pulls a cable that engages the front diff. Put the vacume line and you'll have lights and four wheel drive. (it happened to my blazzer)
Posted on Dec 29, 2008
If Your Front CV shaft is broken it will not engage...Shaft can be in visibly good shape, but you might hear a knocking sound or a shutter when turning sharply. I had this problem this last winter. Get under the truck and try and turn the CV by hand. if it can be rotated, it is bad.
Posted on Jul 05, 2010
Tips for a great answer:
Feb 04, 2011 | 1992 GMC Sierra K1500
Apr 04, 2010 | 2002 GMC Sierra C/K1500
Jan 05, 2010 | 1997 GMC Sierra K2500
Jul 05, 2009 | 1999 Dodge Ram
Jul 04, 2009 | 2002 GMC Sierra C/K1500
Jun 04, 2009 | 1994 Ford F350 Crew Cab
May 26, 2009 | 2003 Ford F150 Regular Cab
May 01, 2009 | 2005 Ford F-150
Dec 20, 2008 | 2000 GMC Yukon
Dec 04, 2017 | 2002 GMC Envoy
60 people viewed this question
Usually answered in minutes!