1000/M74 2011-2012 Chevy/GMC Silverado/Sierra 2500/3500 HD 6.6L RWD – Remanufactured 5-Speed Automatic Trans

Description

Calibrated for commercial rear-wheel diesel routes, GMC Sierra 2011-2012 Remanufactured Transmission units handle 6.6L Duramax turbo-diesel output in 2WD 2500 HD and 3500 HD chassis. This remanufactured 5-Speed Allison 1000 unit manages 460 continuous horsepower, 660 lb-ft maximum torque, and an engine ceiling of 4000 RPM while maintaining internal hydraulic pressure of 230 PSI.

Heavy die-cast A380 aluminum casing encases 3 planetary gearsets forged from carburized 8620 steel. High-energy graphite friction plates with radial cooling grooves suppress heat across forward and reverse clutch packs. Precision-reamed valve body bores house hard-anodized aluminum sleeves to stop internal hydraulic pressure leakage. Sump capacity measures 14.5 quarts of certified automatic transmission fluid, utilizing 1/2-inch cooler lines. Total dry weight measures 325 lbs, fitted with a balanced lockup torque converter.

Key Features of GMC Sierra

Fleet supervisors choose to buy GMC Sierra 2011-2012 remanufactured transmission units to restore solid pulling power in 2-Wheel Drive commercial fleets. Factory reconditioning replaces all wear items to guarantee stable hydraulic line pressure and continuous torque transfer across all 5 forward gear ranges.

• 8620 case-hardened planetary gears resist tooth pitting under severe 660 lb-ft diesel torque loads.
• Radial-grooved friction plates circulate fluid to stop clutch pack burn during heavy vehicle acceleration.
• 14.5-quart fluid capacity stabilizes hydraulic circuit temperatures during continuous interstate highway hauling.
• 2011-2012 Sierra replacement valve body prevents internal cross-leaks across all forward gear ranges.
• Sierra 2011-2012 torque converter package locks fast under load to eliminate slip during highway cruising.
• 5-Speed gearing provides broad mechanical torque multiplication with a 0.71:1 overdrive cruise gear.
• 230 PSI mainline hydraulic pressure locks clutch plates fast to eliminate mid-gear slippage.

Diesel Highway Propulsion Thermal Dynamics

High-flow internal fluid pumps maintain hydraulic mainline pressure between 190 and 230 PSI, keeping sump temperatures between 165°F to 195°F. Input torque absorption handles 660 lb-ft at 1600 RPM without clutch pack slippage. Gear ratios progress from 3.10:1 in 1st gear to a 0.71:1 overdrive gear, keeping Duramax diesel engines in their optimal fuel efficiency zone at highway engine speeds. An external cooler loop sheds excessive heat through 1/2-inch fittings, protecting rotating planetary carriers and needle bearings from high-temperature wear.

2-Wheel Drive Driveline Slip Coupling

A 34-spline rear output shaft links straight with 2-Wheel Drive slip yokes. Rear tailhousing bushing runout is verified under 0.0018 inches on dial indicators, stopping cab vibrations at highway speeds. Die-cast casing mounting pads align flush with standard GM crossmembers, preserving correct universal joint operating angles under full cargo bed weight.

Automated Dyno Validation Maintenance Procedures

Technicians test every unit on an automated spin dynamometer under heavy simulated road load conditions to confirm 5-Speed shift solenoid response, hydraulic line pressure curves, and torque converter lockup holding force. This transmission is not engineered for truck pulls, drag racing, or vehicles running with clogged auxiliary transmission cooler lines.

• Inspect transmission fluid dipstick level and color every 14 operating days.
• Replace synthetic transmission fluid and the spin-on filter every 25,000 miles.
• Flush transmission fluid cooler circuits every 12 months to prevent debris blockage.

Nationwide Commercial Fleet Warranty Terms

A 3-Year unlimited mileage warranty protects commercial fleet owners against premature mechanical defects nationwide. Each heavy wooden transport crate includes the complete remanufactured automatic transmission, a balanced lockup torque converter, a new spin-on external fluid filter, complete installation instructions, cooler flushing guidelines, and fluid specification documentation tags.