Transmission, 6-speed automatic, heavy duty electronically controlled -inc: overdrive, tow/haul mode
Cooler, auxiliary, external transmission oil cooler, heavy duty air-to-oil
6-speed automatic transmission w/OD
Class III/IV trailer tow pkg -inc: 4/7-pin connector, HD flasher, 2" HD hitch receiver, brake module wiring, HD transmission cooler, trailer sway control, HD radiator