uh sorry man but no

 

Yep, which would seem to indicate that they have no idea wtf they are doing.


I sill keep thinking this has something to do with the new pads and rotors that were put on, though I am not sure how.

 

do you have the wild vents problem

 

Yes, I have run into it a few times. The shop I took it to about a month ago before the brakes) did a vacuum test and said everything was fine.

 

I'm as confused as you. After reading the posting it appears that you are shifting the transfer case into 4 hi and then it "pops out" back into 2 hi. Is this correct?

If it is, and I'm basing this purely on assumption of what I've read, the problem isn't in your cad unit or your axle. A posi lock won't help you either. It's either your transfer case, or a problem with the shifter linkage for it. Have you tried using 4 low and does it pop out then?

With the cold temps, you may have ice/frozen mud in your linkage. There could be other fluke issues as well. I know of someone who had a transfer case shifter bolt come loose and fall into the tunnel cavity, causing a similar symptom. Also make sure the CAD switch on the T-case isnt stuck as well.
How old is your T-case fluid? If its the consistency of molasses, it may not let you engage 4hi until its good and warm.

 

Correct. I am ~98% sure it IS engaging 4-Hi but a short period later (turning, accelerating harder, going up an incline) I feel a thunk or hop and I am no longer in 4WD. The indicator light may or may not show intermittently.

Honestly, I have never used 4-Low. I will try it tomorrow.

The transmission and t-convertor assembly were replaces just under two years and 19,000 miles ago, so I would assume the fluids were changed then. It was up to ~+15 today and I still could not get it to go properly in. Considering it operated at these temperatures many times before I would think it is not a general temperature issue.



So, any suggested diagnostics I can do?

 

Well based on you've posted, I'd first not assume anything. Your shop pulled the T-case to remove the tranny and to re-install it. If you didn't pay to have them do anything to the T-case you can bet they didn't.
I'd probably start with the shifter and linkage. The rod is adjustable, and perhaps the lock nuts have lossened. Block the vehicle and set the emergency brake. Try shifting (motor off) into 4 hi, then crawl underneath, pull the linkage rod from the T-case only, and see if you can move it further into gear. You may want to have a helper move the shifter while you observe before removing anything. If the T-case end moves farther than the shifter linkage allows, you may have to adjust it. BTW, you'll need some pliers and a new cotter pin if you remove the linkage
Come to think of it, theres a service manual you can download on this site you can use for this. The illustrations would be helpful.
At this point diagnosis is dicey. If the T-case shifts properly and the linkage is good, you'll have to check for other things. Pull your shift boot and make sure nothing is jammed in the back of the shifter cavity. I'd still check the fluid level. You'll need a 3/8 allen for that(and a level stretch of pavement).
Theres also a snap ring on the tailshaft that can snap and cause issues, but you'd have to drop the rear drive shaft to do it. That's a last resort.
Good luck!

 

I got it back from the shop today. I did not have time or a warm enough place to check out the T-case this weekend.

The shop took a look at it and "repaired" one of the vacuum hoses going to the front differential. When I took a look at it last weekend (without jacks, light, or temperatures above 0) I did not catch anything, so my guess given that they repaired it was that it was something out of my sight. I am dropping by again tomorrow to talk with the mechanic to see if the last shop it was in (where they did the front brakes and rotors) could reasonably have caused it.

I am still thinking about putting in a posi lok this summer just to rule out future troubles.