Broken Transfer Case
Updated February 11, 2008
You can get a rebuilt T-case from Transfercase Express for 1,095.00 exchange.
If the t-case gets over stressed often times from hard btming, the shafts on the planetary gears can break. If one does and the stress is still applied, the whole case goes. Once in Moab I was talking to the Off road america guys. They claimed that they rebuilt the tcase and did something to the gear shafts on their high powered 502 gas trucks.
Another problem is jumping out of gear. This is caused by the nylon inserts on the shift forks wearing out. This wear is sometimes the fault of overheating the case which breaks down the plastic. 
I've been to Moab many times. When I can, I drive around in high unlock until I need the low. I also have a feel for how much I can push the truck. When I use btm (on 98 and older trucks only) I start by using as little as possible and increase it as I need it. As I go over the obstacle I ease off the brake and reduce the btm as I follow through. If I feel that I'm really pushing hard on the brake and giving it a lot of gas I just back off and find another line or go around. You have to know the limits of your truck. You can't do everything with it. Most of my wheeling has been alone and far from home (Illinois) so I can't afford to break down. If I were going to do a lot of rock crawling I would invest in lockers. They put much less strain on your truck then btm.
Pre 95 Transfer cases
Some time during the 1994 year there were internal changes to the t-case. The main shaft is different, with different diameter and splines where the rear drive shaft fits. They are not interchangeable, nor is the rear drive shaft front section.
The spline dia. increase you refer to went into effect with 1995 Gas Job #1, and was a running change for the 1995 diesel. The larger dia. (& capacity) splined shaft was required due to the higher "spike torque" of the gas engine. Under certain conditions, the Gassers would actually twist the splines inside the smaller rear prop.
I have seen several '94 trucks, BTW, with the newer style t-case in it.
And me too, but the ones I'm aware of were used as field replacements. The 1995-2000 T-Case can be used in a 1994 with an easy changeout of the rear propshaft from p/n 6002594 to p/n 6003666. Some simply changed out the slip yoke to p/n 5743957 and used the remainder of their original 1994 rear prop although that would make the overall length approx. 1/2 inch longer than the new propshaft.
Amazingly even after operating with muddy water for a lubricant and then driving 20 miles with no fluid at all, every function still works once the hole is patched up!
Shift Lever Button
My truck in for the T-case cooling loop upgrade. When it came back the shift button on top of the lever has not returned execpt when I put it in park. The truck was just at the dealer today and they told me that there is an internal spring and mine's shot. The solution was an 839.00 shifter assembly. PLEASE tell me there is something else that I can do to fix this problem other then drop 839.00 to fix my shift lever.
I just had the same problem.
1) Remove the shifter. (Make sure you mark all of the wires!)
2) There is a 1" spring that pushes the knob that is probably broken in
half.
3) Go to Napa and get a new spring. (about $0.35)
4) While your there, lube up the shifter and clean out the mud.
5) Reinstall.
Total job= 2 hours
