i need some help... recently, my transfer case has been sticking in 4 wheel, and stays there even when i put the lever back to the 2 hi position... it'll stick for a while in 2wd, and then all of a sudden, it'll hammer out of 4 wheel (it kind of feells like hitting a huge snow chunk or something.. it moves the whole jeep) and my speedometer is going nuts (assuming it has something to do with the speed sensor in the TC) and i'm occasionally getting a shift light flickering on and off in 5th gear. 

i checked it out tonight, and the linkage looks fine, and the rear seal's all good so the fluid should still be full (just changed it) any ideas? or am i going to have to find someones used 231 that they're not using anymore?