S6-S650F Manual Trans for Ford 1999-2000 F-series 7.3L 2WD, 6 Speed

Description

A 5.79:1 crawler low gear paired with 520 lb-ft continuous input torque capability accelerates loaded diesel commercial service trucks up steep highway grades using the ZF S6-650 Remanufactured Manual Transmission built for 1999 to 2000 Ford Super Duty F-Series two-wheel drive work trucks powered by the 7.3-liter Powerstroke diesel engine.

Heavy-duty cast aluminum housing construction integrates an internal trochoid fluid pump that circulates transmission fluid to external cooler cores. Carbon-faced synchronizer rings on second and third gears eliminate shift grind under heavy cargo bed loading. Precision-ground 8620 alloy steel cluster gears absorb severe shock loads from turbo diesel power. Bare dry weight registers 230 lbs. Sump capacity holds 5.8 quarts of synthetic Mercon ATF fluid circulating past magnetic inspection bungs.

Key Features of ZF S6-650

Fleet operations managers choose to buy ZF S6-650 remanufactured transmission units to restore positive manual gear selection to high-mileage diesel work trucks. Complete factory overhaul procedures eliminate gear grinding and shaft deflection under continuous full gross vehicle payloads.

• Internal mechanical lubrication pump protects cluster bearings during continuous heavy towing.
• Carbon-composite synchronizers prevent gear grinding during loaded highway downshifts.
• Induction-hardened helical gearsets absorb 520 lb-ft continuous input diesel torque.
• Upgraded shift detent springs hold shift rails firm to prevent gear pop-out.
• Heavy-duty tapered roller bearings support mainshaft loads under severe tongue weight.
• Integrated bell housing pattern bolts straight to Ford 7.3L Powerstroke engine adapter plates.
• Tested ZF S6-650 gear trains provide quiet gear mesh across all speed ranges.
• Viton front and rear oil seals prevent fluid leaks under high operating temperatures.

Diesel Six-Speed Gearing Torque Capacities

The 6-speed manual gear set provides ratios consisting of 5.79:1 in low crawler gear, 3.30:1 in first, 2.10:1 in second, 1.30:1 in third, 1.00:1 in fourth, and 0.72:1 in fifth gear overdrive. Continuous duty designation supports up to 520 lb-ft continuous input torque at 2,000 RPM. The ultra-low crawler gear enables effortless starts on steep inclines without slipping clutch friction discs. Forced lubrication maintains internal oil sump temperatures below 175°F under severe commercial hauling conditions.

Two-Wheel Drive Driveline Spline Fitment

A 10-spline 1.25-inch diameter input shaft slides flush into standard diesel clutch friction discs without binding. The two-wheel drive rear output shaft accepts standard driveshaft slip yokes with total dial indicator runout held under 0.002 inches. Tailhousing oil seals resist highway grime and prevent fluid loss onto universal joints.

Diesel Transmission Operational Field Guidelines

Inspect clutch hydraulic release cylinder travel to verify complete clutch plate separation prior to vehicle road testing. Replenish the transmission through the side fill bung using synthetic Mercon ATF fluid. This unit is not engineered for closed-course drag strip racing, extreme rock crawling, or gross combined vehicle weights exceeding factory chassis tow limits.

• Inspect casing joints and external cooler fittings for fluid seepage each shift.
• Drain transmission lubricant, clean magnetic plugs, and flush cooler lines every 30,000 miles.
• Check manual shift lever boot and internal pivot bushings every 12 months.

Commercial Fleet Warranty Transit Manifest

Protected by an industry-leading 3-Year / 100,000-Mile commercial fleet warranty covering certified parts and labor. Each heavy wooden shipping pallet holds one remanufactured manual transmission, new throwout bearing, cooler line washers, installation manual, and signed rotational bench inspection report.