2005 GMC SEIRRA SLT Pkg 4WD, Duramax Diesel 6.6 Liter w. 6 Speed Automatic / Manual Option Allison Transmission Short Bed! 2005 GMC SIERRA 2500HD SLT 6.6L Duramax Diesel 4X4 120k MILES Top of the line Sierra. This Beast is powered by a 6.6L 6.5FT bed, Duramax Turbo Diesel, boasting 300 Horsepower and 520ftlb of torque, mated with a powerful and world famous Allison Automatic Transmission!. If a heavy-duty full-size pickup is what you need, This Sierra is the heavy hitter for you, this is a true stump pullin' 4x4! Our Cab boasts a topper, leather upholstery with heated front seats, AM/FM stereo with CD, dual climate control, automatic headlights, and more. Take a look at our photos and see exactly what carries such standard safety equipment as ABS, airbags, and daytime running lights. Free Carfax with every purchase. Credit Union Direct Lender. NO Credit Bad Credit Good Credit Everyone can get approved!