i've heard this is uncommon, and nearly impossible with a two wheel drive, but I did it. I was on my way to work, and thought it would be a good idea to leave some posi-marks because the truck does really good rolling burnouts. under half throttle or better it is not advisable to shift down into first gear with the torque converter locked up. the local transmission shop sold me a used shaft for $40, and i changed it myself. so the lesson was not too expensive, but did take some time. i didn't put in a billit shaft because it was $800, and i can change alot of used shafts for that. just some useful info i thought i'd share. have fun and smoke em down.