All of this happened shortly after replacing the speed sensor (on transfer case)... ABS light came on, brake light came on, speedo qiut, odometer qiut registering miles and the shifts from the auto trans are extremly firm. At start up I have to run the truck in 2nd gear for a bit then manually upshift to OD then it will shift on its own (Still hard though). Took it to the shop and put it on the scanner... that told me low voltage from speed sensor and low voltage from all the wheel sensors. Napa warrentied the speed sensor so I changed it, no changes. Any thoughts before I take it to the shop and have to pay them hourly to search?
Big thanks to all that can help!

02 2500HD
4x4 Crew
6.0 auto

 

Hmm..all those things you described makes it sounds like you should have the fusebox checked out...all of that stuff is electronic so fuse makes the most sense.