I'm really confused now. A couple of weeks ago my 4x4 wouldn't engage. The lights on the dash flashed on and off, but the transfer case wouldn't lock in. From what I was first told, it was probably the transfer case shift motor. Clean or replace, no problem I can do that. I was also told I should get some manual hubs while I was at it. I can do that too.

Here's the problem. I go to replace the shift motor this morning and while I was pulling into my garage I figured I'd give the 4x4 a shot one more time. It worked perfectly. I drove around for awhile and tried it some more. Flawless. The only thing I can think of why it didn't work in the first place is that it was well below freezing when I tried it. Today it's a balmy 40 degrees. I'm thinking that maybe it isn't the shift motor at all. Maybe there's water in the vacuum lines that go to the auto hubs and when it freezes the hubs won't engage.

Am I on the right track here? I don't want to replace a bunch of parts trying to chase down the problem. What do you guys think I should do here?

 

No one?

 

well the vacume hubs are like that from what im told,then tend to not work then work when ever it feels like it

 

I'm not inclined to think it's a vacuum issue. The lights on the dash really don't have anything to do with the 4WD vacuum function, and if they were flashing, then there was - at that time - some sort problem in the circuit that controls the transfer case motor. Maybe the cold weather was affecting the motor itself.

 

Well, I already have the new motor. Might as well put it in and see if it works when it gets below freezing. I'll just have to put some manual hubs on the ol' Christmas list.

 

Actually, I have to qualify my last post. There is an electrical problem that could affect vacuum to the hubs. An open or short in the PVH solenoid circuit would also cause the 4WD lights to flash and codes to be stored in the GEM.

 

So then manual hubs would be a better solution?

 

i have the same problem,imn getting them..although i hear and see the 4x4 but it dosnt lock my hubs

 

Neither the AVM manual hubs nor the stock auto hubs are much good unless the TC is engaging. So you have to be sure it's not a TC issue.

 

Do I need to take it to a dealer to have the transfer case diagnosed, or will my X-cal 2 do it? I can hear the realays clicking behind the dash and it seems like the 4WD is engaging above freezing.

 

I don't think the X-cal will pull codes from the GEM. But before you go get wacked by the dealer, check over a few things first. Look over the 4WD-related fuses (#s 9, 10, 26, and 27 inside the cab fuse box, and # 3 located in the power distribution box under the hood). Check out the harness connectors to the TC and the PVH solenoid. Makes sure there's no moisture corrosion etc. that could be affecting the circuit(s) at those points.