Torque converter went out. I always use engine braking to slow down when coming to a stop sign shifting from drive to second and then to low and finally using brakes. On accelerating from the stop sign I inadvertently placed transmission in neutral and then stepped on the accelerator thinking the transmission was in Drive. Needless to say the diesel engine accelerated to high speed. I dropped the transmission back into Drive without allowing the engine to drop RPMs which was when I lost the converter. Seems the torque converter wasn't able to handle the high RPM of the engine with the wheels still at a low speed. Stupid thing to do. Had to coast about 300 yards to get off a bridge and finally was able to pull over on shoulder.
4 speed Allison and 8.2 L Detroit