Comparing Truck Traction Control SystemsThis area of the track was used to compare truck traction control. The white pavement had water running over it so that drivers could position a truck's left or right-side tires on the wet area, but keep the the other side of the pickup on dry pavement.
When we accelerated, the tires sitting on the wet strip spun. The Ford F-150 truck in the photo spun so much that its tires started smoking, even though there was water underneath them.
Test trucks had different systems for controlling traction: limited slip differentials, electronic traction control, and GM's automatic locking rear differential. This was a GM event, so it's not difficult to guess which trucks handled the hill best. The GM differential works real well, with smooth engagement and disengagement and no noticeable jerking, excessive noise or other negative side effects.
GM's Traction SystemGM's automatic locking rear differential senses the spin of one wheel and locks both axles together to send power to the wheel with traction. The Sierra I drove made a couple of lurches, let out a little sound, and then climbed the hill with no spinning and no smoke.