The Chelsea 281GMFJW-B8RZ is a 281 Series PowerShift (hydraulic) hot-shift power take-off engineered for automatic transmissions with a 10-bolt aperture, including Allison applications. The 281 Series carries a continuous duty torque rating of up to 390 lb-ft and delivers output power of 56 HP or greater. The unit mounts via a 10-bolt configuration and is available with multiple output types including SAE B and SAE C pump flanges, ISO 7652 pump flange, and driveline outputs. The 281 Series features a ductile iron bearing cap rated 117% stronger than gray iron, an o-ring sealing configuration between the housing and bearing cap, and an 80% thicker steel clutch pack disc compared to its predecessor. Common markets include fire and rescue, refuse, truck cranes, and pumper-cleaner applications.
Features
10-bolt mounting for Allison and compatible automatic transmissions
PowerShift hydraulic shift, hot-shift capable, continuous operation rated
Continuous duty torque up to 390 lb-ft (529 Nm); output power 56 HP or greater
Ductile iron bearing cap, 117% stronger than gray iron predecessor
O-ring seal between housing and bearing cap for improved clamp load
80% thicker steel clutch pack discs to resist premature wear
Tech Specs
- Mounting Type: 10-Bolt
- Shift Type: PowerShift (Hydraulic), Hot-Shift
- Continuous Operation: Yes
- Continuous Torque: Up to 390 lb-ft (529 Nm)
- Output Power: 56+ HP (51+ kW)
- Shaft Power: 37 HP at 500 RPM / 74 HP at 1000 RPM
- Output Types: SAE B Pump Flange, SAE C Pump Flange, ISO 7652 Pump Flange, Driveline
- Output Shaft Options: SAE B (7/8 in. - 13T), SAE C (1-1/4 in. - 14T), 3/4 in. - 11T Pump Spline, 1-1/4 in. Round Shaft with 5/16 in. Key (SmartStart), 1410 Companion Flange
- Lubrication: Pressure Lube and Wet Spline options available
- Transmission Compatibility: Allison automatic transmissions (10-bolt aperture)
- Speed Ratios: Nine available, including low and high speeds
- Bearing Cap Material: Ductile Iron
Additional Information
The 281 Series is Chelsea's evolution of the top-selling 280 Series PTO, with structural and sealing improvements aimed at handling vibrational effects from modern engine designs. Available features include SmartStart (reduces shock load at start-up), Electronic Overspeed Control (EOC) to protect driven equipment, and a wet spline lubrication option rated for 7 to 10 times greater shaft life versus standard spline configurations. Rotatable cast iron flanges improve pump clearance during installation. Typical markets for this series include fire and rescue, refuse collection, truck cranes, and pumper-cleaner units. Reference documents: 281/288 Series Parts List HY25-2281-M1/US; 267/281/288/871/878 Series Owner's Manual; Chelsea PTO Stud Kits HY25-2002-M1_US.Parts Manual: Chelsea 281 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
