Ranging in SL, SLE and the more luxurious SLT trim level, the 1999 GMC Sierra 2500 Crew Cab pickup truck boasts itself on a 154.5 inch wheelbase on 16-inch wheels. With seating for up to 6 passengers is a front bench seat, the 1999 GMC Sierra 2500 Crew Cab in the SL provides only vinyl seating coverings along with standard AM/FM radio. On SLE models, seating is upgraded to stain resistant cloth on the 1999 GMC Sierra 2500 Crew Cab. Other standard features on the 1999 Sierra 2500 Crew Cab in SLE trim includes air conditioning, power windows and mirrors as well as cruise control. The SLE standard features are added along with leather seating to the GMC Sierra 2500 Crew Cab SLT model. Providing a base 255 horsepower, the 1999 GMC Sierra 2500 Crew Cab standard power is furnished thanks to a 5.7 liter Vortec V-8 engine. Fed through a standard five-speed manual gearbox, a four-speed automatic is also available. Engine options on the 1999 Sierra 2500 Crew Cab includes a 290 horsepower 7.4 liter gasoline engine as well as a 6.5 liter turbodiesel engine producing upwards to 430 foot-pounds of torque. Trailer pulling capability of the 1999 GMC Sierra 2500 Crew Cab is rated between 7,000 to 10,000 pounds.