The Chelsea 899HAFJW-M5XS or 899HAFJWM5XS is a constant mesh power take-off assembly engineered specifically for Allison 4700 Series transmissions. Mounting via a 10-bolt pattern, this 899 Series unit positions the SAE C pump output flange at the rear of the transmission, moving the PTO/pump interface rearward to create better pump clearance between the transmission and the frame rail. The one-piece main shaft eliminates input splines between the PTO body and the output extension. The SAE C output uses Wet Spline Technology to extend shaft life under demanding duty cycles. Continuous torque reaches up to 670 ft-lbs; intermittent torque is rated at 501+ lb-ft. Shaft power output is 64 HP at 500 RPM and 128 HP at 1,000 RPM. Common applications include aerial trucks, fire and rescue vehicles, truck cranes, refuse trucks, and snow and ice equipment. Call us to confirm proper fit for your specific Allison 4700 configuration.

• Transmission: Allison 4700 Series
• Shift Type: Constant Mesh
• Mounting Type: 10-Bolt
• Outlet Flange Type: SAE C
• Output Shaft Type: SAE C, 1-1/4 in. - 14-tooth Pump Spline (Wet Spline)
• Continuous Torque: Up to 670 ft-lbs (check application pages for actual torque ratings)
• Intermittent Torque: 501+ lb-ft / 501+ Nm
• Output Power: 56+ HP / 51+ kW
• Shaft Power: 64 HP (48 kW) at 500 RPM; 128 HP (95 kW) at 1,000 RPM
• Lubricant: Wet Spline

The 899 Series mounts like a standard side-mounted PTO but adds a support bracket at the rear of the transmission. The housing and gear section tucks tightly against the transmission, locating the pump interface at the rear to create clearance between the unit and the frame rail. This design suits applications where both pump space and high continuous torque are critical requirements, including aerial platforms, fire and rescue apparatus, pumper cleaners, truck cranes, and refuse trucks. The 899 Series supports Allison 4700 transmissions configured with or without a cooler, a retarder, or both.