First issue...4x4 light is coming on without shifting T/C could get light to go off by shifting through thru the T/C, then that didn't even work...after a couple more times of the light coming on it sounded like the front end was trying to engage. Called Chevrolet and ordered the indicator switch on the top of T/C (said they can get to sticking). So while I wait on that to get here...I simply unplugged the front diff acuator(no more light coming on) so I think I am safe until switch gets here...
Yesterday I am pulling of a stop sign with firm accelleration and the ABS and the brake light on the dash come on and the speedo falss to 0 and is unresponsive. At the same instant all the shifts from the auto trans now are extremly firm, finished my trip to town and nothing "fixes itself".
One thing lead to another or just two seperate deals?
02 2500HD 6.0 Helps when you put the vehicle description in...too many things on my mind I guess

6/3/10 Update: Replaced indicator switch on T/C and plugged in front end, only drove a couple of miles and no 4x4 light coming on. I think one problem is fixed. I took a look at the speed sensor on the rear of T/C and it had fluid in the plug area so after some thread searches about the other issue I am having I replaced it as well.
Still in desperate need of some insight as to why or what is wrong with the ABS light coming on instantly and the brake light to come on shortly after? Speedo is still not working at all and tranny shifts are extremly firm. All of this happened at the same moment.

 

Hard to give you much info when we dont know that make model, year , and what motor is in it.