I have suspected that my 4 wheel drive system was not working, but I confirmed it last week. Today I had a chance to crawl under the truck and look around. I knew the CAD was not engaging and the indicator light wasn't lighting up, so I figured it had something to do with the vacuum system. Put a vacuum pump on the CAD and got it to work. Put a gauge on the actuator line and no vacuum. This meant there was a loss of vacuum somewhere down the lines, so I started disconnecting the rubber lines to check them and using high pressure air I checked the steel lines in between. Everything checked good so I traced back to a switch on top of the transfer case. Of course, there's no mention of it in the FSM. This switch changes the flow of engine vacuum to/from the vacuum motor on the CAD dependent on where the transfer case shift lever is to engage/disengage the CAD. I tried using a different vacuum line just to test it and still no go. Because it is on top and real close to the tranny hump there's no way to get a gauge or pump on it to test it. I used a cutoof 1-1/16" wrench to get the switch out. Not easy.

Once on the bench I tested the switch with a vacuum pump and it would not hold vacuum in any position. This means it is leaking through the switch body somewhere and that's why my CAD is not working. Went to the dealer and while they usually stock this part, they were out. Will be here on Friday. Had to put the bad one back in because fluid can come out of it. Glad I haven't had a chance to do any wheeling yet because I would have been stuck in 2 wheel drive. One good thing is I took the time and finally put in my oil filter adapter for my oil temp. gauge. Ran the wires and now both gauges are online and working great. Engine oil runs about 10 degrees hotter than the tranny oil, but has yet to go above 180. I can't believe how cool this truck runs even with the outside temps near 100.

 

You actually get your truck dirty!?

Wow....

The CAD and vacuum thing is a weird design, but at least you don't have to mess with lockers... The little vacuum lines on the transfer case skid plate that run to the CAD came off awhile back (might be due to mud caked in there) and my 4x4 light was always on and sharp turns were difficult. Figured that out when my started wouldn't turn over and I went underneath to look for broken/unplugged wires (turned out to be the trans temp sensor or something [it was a three wire connector on the tranny pan]). Interesting placement of the vacuum lines, not very off-road friendly.


Anyway, good luck replacing the switch.

 

It's actually filthy right now.

I'd take a set of locking hubs over this shift-on-the-fly crap any day. All that CAD BS is so vulnerable to getting yanked off by a tree branch or other offroad debris and I have my doubts about how strong the coupler and shift fork are. All this complexity might make for more convenience, but I really liked the simplicity of my old Power Wagon. When going offroad we just locked our hubs beforehand and then if we encountered some nasty terrain we'd just shift into 4X without having to get out of the truck. I'm going to go wheeling this weekend and get it nice and dirty just for you.

 

Awe, thank you

 

better take pics.....dirt always looks better on a white truck

 

its hard to imagine your truck with even a little splatter of mud on it, i want to see some pictures.

 

Here's one from last month.

 

i remember that one but it just looks like you went down a dirt road with a little water on it. and iirc it drove you crazy having mud on your truck.

 

that aint nothin, and that sticker looks like the one i have on my truck

 

So! What's yer point?