2nd Gen Non-Engine/Transmission 4 wheel drive light problems

[blkdragon]

I got new front roters put on my 99 and when i got my truck back the 4 wheel drive light was on and it has been on for about a year. I unplugged the light so it wasnt on and then i went to get my truck aligned and the tire place said that the alignment wasnt off to bad. And my truck still pulls some. My tires are also wearing more than they should be. My 4 wheel drive light will not go off unless i unplug it from the front drive shaft. But my 4 wheel drive has always worked. I cant get my hubs to unlock. If anybody can help i would appreciate it.

 

[JSienkowski]

Sounds to me like the vacuum servo for the CAD is either stuck or has a vacuum leak-but I'm new to the vacuum engaged stuff-my last truck had manual hubs.

 

[blkdragon]

can anybody else help me with this problem

 

[BJMarshall]

A simple way to check is to swap the vacuum lines. I have replaced several of the switches on the transfer case because they were bad and were keeping the CAD connected all the time. The two lines you want to switch are on the crossmember in front of the tansfer case. There, two rubber lines connect to two metal lines. Pull them loose. You should have vacuum on one of them with the truck running. If you have no vacuum, your problem is elsewhere. If you have vacuum, reverse the hoses. Move your truck back and forth a little and see if the light goes out. If it does, the switch in the transfer case is bad. If it doesn't change, the CAD is most likely the problem.

 

[blkdragon]

What is the CAD and what does it do

 

[nps]

Center Axle Disconnect. The bulge in the front axle tube on the passenger side. It unlocks the pass side outer axle via a splined collar when in 2wd. Because it is an open diff, the pass side tire is like it is in the air, thus only the side gears spin - not the ring/pinion/front driveshaft when in 2wd. When in 4wd the collar locks the pass side axle and then everything is as-is with any other open diff. They quit putting the CAD on late 2002 trucks. None of the 3rd gen have them - the front driveshaft always spins even in 2wd.



The 4wd light switch is part of the CAD if you have a CAD. Until the collar engages via a vacuum motor the light will not come on.

 

[blkdragon]

Thanks Guys I will take a gander at it. Hopefully i can accomplish it.