My 97 K2500 (6.5 dieslel) has been having some odd problems lately. A few weeks ago I went to pick up a trailer from a friend. The car drove fine on the way over. On the way back as we got onto the freeway we found it was not shifting out of 1st. Even manually shifting into 2nd or 3rd would not do anything. We hit the hazards to limp on the shoulder to the next exit - when the hazards were turned on, the gauge cluster flipped out. the tach and speedo bounced around, the gauge lights flickered and the engine actually started to run rough. We pulled off into a gas station and checked the trans fluid - it was full. we pulled the combination meter relay and the hazards fuse. We also unplugged the trailer connection. After all that the truck still would not shift out of first. The next thing we tried was driving it in reverse, putting it into 4H and 4L which didn't do anything. The last thing we tried was turning the truck off and on. Of course it wouldn't start. absolutely nothing, not even a click. There was a weird buzzing sound, like the door chime module or seatbelt module wasn't getting full power. but that was it. We then disconnected the battery, and clipped the wires for the electronic brake controller (which is what we were suspicious of due to its poor installation and the fact that the trailer had electronic brakes and the problem only happened once the trailer was connected). Once this was done the truck fired right up and shifted fine. It worked perfectly for the next week. Then this weekend I went to pick up a different trailer. About 20 mins of driving with that trailer the problem came back. The first clue was the tach was bouncing and settling on 0 rpm's while driving. then it stopped shifting again. We pulled over, found some wiring left over from the brake controller, removed it and it seemed to be ok. A little later the problem came back but this time the truck got stuck in 2nd instead of first. We parked and messed around with the wiring for a long time. When we started it, it ran fine and shifted fine - we hadn't really changed anything. We drove some more but then the problem came back, we were about 4 miles from a parts store so we limped it along - as we got closer the car lost more and more power and the gauge lights got very dim - almost like a dying alternator. we pulled the alt in the parking lot and had it tested - it was fine. we tried starting it again and it drove fine, shifted and everything - the only thing was we were missing the gauge cluster lights. Thats where it is now. It seems like it must be a grounding issue to me. any other ideas?
Grounding, check to see if battery cables have worn through any where. Starter leads too. The Jeep I used to have did this once and all it turned out to be was crappy corroded old cables.
