The Chelsea 899 Series PTO Assembly, part number 899HAFJW-M5XK or 899HAFJWM5XK, is a constant-mesh power take-off designed specifically for Allison 4700 Series transmissions. The 10-bolt mounting configuration positions the pump output to the rear of the transmission, moving the SAE C flange rearward to improve clearance between the pump and the frame rail. An additional bracket at the rear of the transmission provides support. The output shaft is a SAE C ("XS") wet-spline design, extending spline life under demanding duty cycles. Continuous torque capacity reaches up to 670 ft-lb (check application pages for actual torque ratings), with intermittent torque rated above 501 ft-lb. Shaft power measures 64 HP at 500 RPM and 128 HP at 1,000 RPM. Common applications include aerial trucks, fire and rescue, refuse trucks, and truck cranes. Call us to confirm proper fit for your specific Allison 4700 configuration.
The Chelsea 899 Series is suited for aerial, fire and rescue, refuse, and truck crane applications that require high torque output in tight pump-clearance environments. The one-piece main shaft eliminates input splines between the PTO body and the output extension, reducing potential wear points. The unit can be ordered for Allison 4700 transmissions equipped with or without a cooler or retarder, or both. Contact Pro Gear and Transmission to confirm the correct configuration for your transmission build.
Features
Designed for Allison 4700 Series transmissions, 10-bolt mounting
Constant-mesh (non-shiftable) operation
SAE C ("XS") wet-spline output shaft for extended pump spline life
Continuous-duty torque capacity up to 670 ft-lb (verify actual rating on application pages)
Intermittent torque rated above 501 ft-lb
Rear-positioned pump flange improves clearance between pump and frame rail
Tech Specs
- Transmission Application: Allison 4700 Series
- Shift Type: Constant Mesh
- Mounting Type: 10-Bolt
- Outlet Flange Type: SAE C
- Output Shaft Type: SAE C ("XS") Wet-Spline Output
- Continuous Torque: Up to 670 ft-lb, 908 Nm (check application pages for actual torque ratings)
- Intermittent Torque: 501+ ft-lb, 501+ Nm
- Output Power: 56+ HP, 51+ kW
- Shaft Power at 500 RPM: 64 HP, 48 kW
- Shaft Power at 1,000 RPM: 128 HP, 95 kW
Additional Information
The Chelsea 899 Series is suited for aerial, fire and rescue, refuse, and truck crane applications that require high torque output in tight pump-clearance environments. The one-piece main shaft eliminates input splines between the PTO body and the output extension, reducing potential wear points. The unit can be ordered for Allison 4700 transmissions equipped with or without a cooler or retarder, or both. Contact Pro Gear and Transmission to confirm the correct configuration for your transmission build.
Parts Manual: Chelsea 899 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
