One problem related to automatic transmission torque converter has been reported for the 2000 GMC Sierra. The most recently reported issues are listed below.
On 12/13/99 when slowing down to make a left turn, the tourque converter locked up and stalled the truck in middle of traffic while crossing the left lane. With difficulty, truned the wheel back to the right and pull off the road and shifted into park and restarted the truck. Luckly there was very little on coming traffic. On 2/11/00 while coming into a rolling right hand turn and going about 15 mph, I started to brake and the tourque converted again locked up and the engine stalled. Again with difficulty I was able to steer into the corner and make the corner. As the truck was free rolling it just started itself and it contiuned on, almost crached into two cars waiting at the stop sign. If my wife was driving there would have been a collision. In October when waiting for a traffic light to change, I accellerated and truck didn't move. I stepped on the brake shifted to park and then back to drive and it finally went into gear and moved. Have been back to the dealer twice with tourque converter concerns with no solutions. Gm has a transmission problem with there 4l60e transmissions. My 1998 GMC jimmy has been replaced at 19000 miles. Am very worried that this will happen at any time when not ready and an accedent will happen.