1000/M74 2001-2002 Chevrolet/GMC Silverado/Sierra 2500HD 3500 8.1L RWD – Remanufactured 5-Speed Automatic Trans

Description

Calibrated for heavy rear-wheel propulsion, Allison 1000 Remanufactured Automatic Transmission units for 2001-2002 GM 2500HD and 3500 8.1L two-wheel drive chassis transfer huge gas torque. This remanufactured unit handles 400 continuous input horsepower, 520 lb-ft maximum input torque, and 4800 RPM maximum input engine speed while maintaining mainline hydraulic pressure of 230 PSI.

High-strength cast aluminum casing protects three planetary gearsets manufactured from carburized 8620 steel. Segmented friction discs with precision spiral oil channels prevent heat build-up across all forward and reverse clutch packs. Machined valve body bores receive hard-anodized sleeves to prevent pressure loss and shift flare. Transmission fluid volume requires 14.5 quarts of approved automatic fluid through 1/2-inch cooler ports. Dry weight measures 325 lbs without fluid, fitted with a heavy two-wheel drive output extension housing.

Key Features of Allison 1000

Fleet managers choose to buy Allison 1000 remanufactured automatic transmission units to maintain fleet uptime across heavy utility truck operations. Complete engineering renewal eliminates valve body cross-leaks and restores crisp hydraulic shift timing across all gear selections.

• 8620 alloy steel planetary gears absorb continuous 520 lb-ft gas engine torque without tooth root fatigue.
• High-energy friction plates disperse heat to stop clutch pack slippage under maximum gross vehicle weight.
• 14.5-quart fluid capacity stabilizes hydraulic pressure across extreme commercial hauling cycles.
• Sleeve-reinforced valve body prevents line pressure drop in this remanufactured Allison 1000 unit.
• 5 forward speeds step from 3.10:1 in first gear through 0.71:1 in fifth gear overdrive.
• 230 PSI mainline hydraulic pressure guarantees positive clutch clamping under wide-open throttle acceleration.
• Precision balanced slip yoke output bushing prevents driveline vibrations at highway corridor speeds.

Hydraulic Line Pressure Torque Dissipation

A high-output internal fluid pump maintains mainline hydraulic pressure between 190 and 230 PSI, keeping fluid sump temperatures between 165°F and 195°F. Input torque absorption handles 520 lb-ft at 3200 RPM without converter slip. Gear ratios range from 3.10:1 at launch to 0.71:1 in fifth overdrive, reducing engine revolutions per minute on open highways. The auxiliary fluid cooling system dissipates thermal energy through 1/2-inch ports, keeping planetary needle bearings cool and preventing clutch pack friction material breakdown under severe highway pulling.

Two-Wheel Drive Driveline Slip Coupling

A precision-ground 34-spline output shaft interfaces with two-wheel drive slip yokes. Rear tailhousing bushing runout is held within 0.0018 inches on dial indicators, stopping vibration down the driveshaft. Standard GM crossmember mounting pads position the transmission case flush against chassis brackets, preserving accurate universal joint angles under full cargo loads.

Dyno Load Testing Maintenance Guidelines

Every unit completes rigorous hot-fluid dynamometer verification under varied simulated vehicle weights on our computerized test cell to confirm shift solenoid activation, mainline hydraulic pressure, and positive torque converter lockup. This transmission is not engineered for radical drag strip launches, tractor-pulling modifications, or driveline setups with restricted transmission fluid cooling radiators.

• Check transmission fluid level and clarity with the dipstick every 14 operating days.
• Replace synthetic fluid and the external spin-on fluid filter every 25,000 miles.
• Flush transmission fluid cooler circuits every 12 months to eliminate accumulated friction dust.

Commercial Crate Manifest Warranty Terms

A 3-Year unlimited mileage warranty protects fleet buyers against material defects and hydraulic failure. The rugged wooden transport crate holds the remanufactured automatic transmission, a balanced lockup torque converter, an external spin-on fluid filter, a quick-start installation packet, and oil fill capacity tags.