Yeah, I put it in 4L and drove down a side road and steered back and forth and I cant feel the front tires "gripping" or anything. Same thing with 4H now, except there is an extra strain on the enging in 4H.
Thanks!

 

Well, there's really only one way to tell if it's working properly...get it on dirt or mud, put it in 4L, and gun it. If only the back tires spin, then you know it's not working right. Try the same test for 4H.

 

I'll do that once I find some. Thanks!
Now my cab light burned out.

 

No need for mud, put it in 4wd on dry pavement in a parking lot, turn sharp, if front is locked in it will hop.

 

Yeah, thats what I meant in my post above. I cant get the front wheels to hop, yet their is a little strain on the engine when in 4H even though its not actually engaged.

 

OK, this is SUCH a simple thing to troubleshoot.

1) Jack the front end up in the air and set it on jack stands.
2) Start the engine, let it idle in neutral, and engage 4 high.
3) Crawl back underneath and see if you can turn the front driveshaft. If so, the transfer case is not locked. If not, the t-case is locked.

4) Next, try and rotate one front wheel. If the wheel on the other side turns the opposite direction, the center-axle disconnect is linked and everything is fine. If only one wheel turns, the center axle disconnect is not engaging, and there is a problem.

5) Repeat those checks idling in 4 low.

-Joe

 

simple test, and to add to it, if you drop the truck down and it takes off, that means you forgot to turn the engine off when you dropped the truck

 

Better idea: Jack all four wheels up, put it in 2wd, see what wheels spin. Repeat for 4H and 4L.

 

His is a manual. Should he forget to turn it off, it may roll, but it'll hardly take off....

 

forgot about that. But it did happen to one field technician I knew. The guy got out of his truck and forgot to put it in park......the truck was in reverse and nearly ran over him. The guys working with me called me as it was going on and they were laughing hard

 

Okay thanks guys!! I'll try that tomorrow.

 

From what I understand, when you put it in 4h or 4lo a signal then goes from the transfercase switch to the solenoids under the hood which control the vaccuum to the axle disconnect.

It sounds like you are getting a signal in 4hi from the transfer case but not in 4lo even though the transfer case is going into low range. Everything mechanical seems ok.

Try searching on this I have read about it on here before. And the jack up the truck method above works best for trying the 4x4 out.

 

By that I meant one month later, today.

I put the front end up on jack stands today, idled her in neutral in 4H and could not move front drive shaft. One wheel would spin but not the other. Now, behind a black plastic cover underneath the truck is what looks to be a vaccum champer with two lines going to it. On the right side of it, I can push this piece in (has a rubber boot on it.) After I push it in, I can spin one tire and the other one will spin in the opposite direction. Then I can pull it out to disengage. Thats probably my problem right there. I just have to figure out why that piece is not moving.

Any help is still appreciated! Thanks!

 

OK, simple enough: It's a vacuum issue.

On the firewall, passenger side, there are two vacuum solenoids. One engages the CAD, and one disengages the CAD. I'd start there. Pull the vacuum lines that run down to the CAD off the solenoids, start the engine, and you should have vacuum on one and only one of the solenoids. Then, switch to 4wd, and you should have vacuum ONLY on the other one. I suspect that either the engage solenoid is stuck, failing to provide vacuum, or the disengage solenoid is stuck, and doesn't STOP providing vacuum when you shift to 4high. If you have vacuum on both sides of the diaphragm on the front end (or, conversely, no vacuum on either side) it won't lock the front axle, and will act like you have a broken axle shaft. (because, well, you do.)

Now, if the solenoids aren't working properly, before you replace them, there's one more thing to check: Pull the plugs off, and check for 12V on one wire, and ground on the other when it should be activated. The GEM grounds the solenoids to open them. If you're not getting a ground to the vacuum solenoids, that'll stop them from actuating the CAD as well.

Now, if the solenoids check out, you'll want to check for vacuum at the CAD end of the vacuum hoses, tracing along their length looking for cracks and breaks. In my experience on these boards, about 1/2 the time one or both of the solenoids has failed, and the other 1/2 of the time, it's a cracked, broken, or battery-acid-eaten vacuum line. The CAD can also get sticky, but you probably would have noticed that when you were playing with it manually.

Let us know what you find!

-Joe

 

Thanks a lot Joe! I'll give it a try soon.