Hey all, So my 4wd was working perfectly fine until I had to replace my front axle wheel bearings. Since I installed the new wheel bearings the 4wd light is on constantly on the dash when in 2h. When I switch to 4h nothing happens I'm still in 2h but when I flip to 4l it goes to 4l. Dash light is on no matter what gear the transfer case is in. I just replaced the wheel bearings. Touched nothing else. Could I have bumped something I don't know about to make this stop working? I did have a sledge hammer in there to get the old wheel bearings out. Thanks for any help.

 

Make sure the Central axle disconnect isn't jammed one way or the other from removing the shafts.

 

Pull the two vacuum lines off of the CAD, verify that you have vac. on one line in 2H, and vac. on the other line in 2L. If so, pull the CAD and see what you have going on in there. Make sure to check that the bushing is in place in the end of the outer axle. Push the two vac. lines back on while the CAD's off and check to see that it's working normally by shifting back an forth between 2H and 2L.

 

Thanks for the replies. Will be attempting this hopefully today or tomorrow. I've still had no luck since. I don't see how I could of lost any vacuum as I just changed the wheel bearings but its worth a shot. Need the 4w back with all the snow we just got dumped with. Thanks.

 

I don't think it's vac. related either, but worth checking while you're at it, only takes a minute. More like the shift collar fell off and has the shift fork jammed against the indicator switch, or something similar. I think the problem will be obvious once you pull the CAD.

 

All vacuum lines look okay. I did disconnect the harness that had 4 lines and I heard air when I pulled it off. Red, Green, Black & Grey. I take it each one is for the 4 positions. Shift linkage is working properly. It does engage in 4L, N, and 2H. The only one thats not working is 4H and to note the 4wd light is on the dash in all positions including 2H.

I'm wondering if the line for 2H just has a leak somewhere.

 

As posted pull the CAD, the collar is not in the right position.

 

The CAD (central axle disconnect) is that the vacuum shift motor? No where in my haynes manual can I find CAD.

Thanks guys. I just needed to understand how this system works. This is making complete sense now. Thanks all. No time today will have a look tomorrow morning and keep you posted.

 

Yes thats what CAD stands for when it comes to these trucks.

 

I think maybe when you put the axle shaft back in after replacing the bearing you might of jammed the shift collar on the cad or something causing the light to stay on and for it not engaging.

Also be careful when you remove the cad there are 4 bolts that can break off pretty easily, I broke 2 when installing my posi-lok. I would use some pb blaster and maybe some heat before attempting. Good luck!