I bought a 1995 gmc 2500 4x4 last fall with a 5.7 liter and 4L80E. It was not running at the time and had been sitting for at least a year as of October 2001. I ended up putting a rebuilt engine in it this spring. I drove it for about 100 miles, and everything was fine. It ran and shifted properly. The only issue for those 100 miles was that the oil pressure gauge, and temp gauge would peg all the way to the right as soon as you started the engine. I periodically checked the coolant temp at the thermostat housing with an infrared thermometer and it was always around 185. Last night I was headed into town, and the transmission stopped shifting. Reverse works fine, but it will not shift out of 1st gear. I tried manually moving the shift lever from 1 to 2, etc and it had no effect. It is full of bright red fluid. I tried to retrieve any codes using the paperclip method, and it didn't display any codes other than the normal "12" code. I would prefer to troubleshoot and repair this myself, but I'm having a hard time finding troubleshooting guides that are written in plain english with pictures for a semi literate individual like myself. I am toying with the idea of just ordering all of the solenoids, speed sensors, a wiring harness, and a new filter from rockauto and throwing them in, as it would probably cost less than even having a shop look at it. Any tips, links, starting points, etc would be much appreciated.