fallguy

I have a friend that is just putting the finishing touches on this drag car. He tried to drive it the first time and when he put it in gear it immediately killed the motor. It runs fine in neutral or park, but as soon as it goes in gear it kills it. He think problem with torque converter. We put it on jack stands and then started it and then put in gear and it worked, but as soon as any load is put on it, ie on the ground, it pulls the motor down and kills it. He bought the tranny used but said it was rebuilt. It's a powerglide. The torque converter is brand new. Any ideas?

thanks!