The Chelsea 281 Series Power Take-Off, part number 281GMFJP-B3RS or 281GMFJPB3RS, is a hydraulically shifted hot-shift PTO designed for automatic transmissions with a 10-bolt aperture, commonly found on Allison transmissions. Built as an evolution of the Chelsea 280 Series, the 281 Series introduces a ductile iron bearing cap rated 117% stronger than gray iron, an O-ring sealing configuration between the housing and bearing cap for improved clamp load, and an 80% thicker steel clutch pack to resist premature tooth wear. Nine speed ratios cover both low and high-speed applications. Electronic Overspeed Control (EOC) and an optional wet spline lubrication system round out the protection features. A genuine Chelsea part, available from Pro Gear and Transmission. Call us to confirm proper fit for your specific transmission application.
The Chelsea 281 Series is an evolution of the proven 280 Series platform. Key design improvements include the ductile iron bearing cap (117% stronger than gray iron), an upgraded O-ring seal between the housing and bearing cap, and an 80% increase in steel disc thickness within the clutch pack. These changes directly address vibrational forces generated by modern engine designs. The series supports multiple output shaft types including SAE B (7/8"-13T pump spline), SAE C (1-1/4"-14T pump spline), 1-1/4" round shaft with 5/16" key (SmartStart), and 1410 companion flange for driveline outputs. The Positive Stop feature on driveline outputs eliminates oil seal damage from coupling over-travel. Reference documents: 281/288 Series Parts List (HY25-2281-M1/US) and the 267/281/288/871/878 Series Owner's Manual are available from Parker Chelsea.
Features
Ductile iron bearing cap rated 117% stronger than gray iron
Hydraulic (PowerShift) hot-shift operation for 10-bolt automatic transmission apertures, including Allison
O-ring sealing configuration between housing and bearing cap improves clamp load and reduces vibration effects
80% thicker steel discs in the clutch pack resist premature tooth wear
Nine speed ratios available, including low and high speeds
Electronic Overspeed Control (EOC) protects driven equipment; wet spline lubrication option provides 7 to 10 times greater shaft life
SmartStart reduces shock load at start-up for select applications
Tech Specs
- Mounting Type: 10-Bolt
- Shift Type: Hydraulic (PowerShift) Hot-Shift
- Transmission Compatibility: Allison automatic transmissions (10-bolt aperture)
- Continuous Operation: Yes
- Continuous Torque (Series Rating): 390 lb-ft (529 Nm) - verify actual rating on application pages
- Output Types: SAE B Pump Flange, SAE C Pump Flange, ISO 7652 Pump Flange, Driveline
- Speed Ratios: Nine ratios including low and high speeds
- Shaft Power: 37 HP at 500 RPM / 74 HP at 1,000 RPM (28 kW at 500 RPM / 55 kW at 1,000 RPM)
- Lubricant Options: Pressure Lube, Wet Spline
- Typical Markets: Fire and Rescue, Truck Cranes, Pumper/Cleaner, Refuse
Additional Information
The Chelsea 281 Series is an evolution of the proven 280 Series platform. Key design improvements include the ductile iron bearing cap (117% stronger than gray iron), an upgraded O-ring seal between the housing and bearing cap, and an 80% increase in steel disc thickness within the clutch pack. These changes directly address vibrational forces generated by modern engine designs. The series supports multiple output shaft types including SAE B (7/8"-13T pump spline), SAE C (1-1/4"-14T pump spline), 1-1/4" round shaft with 5/16" key (SmartStart), and 1410 companion flange for driveline outputs. The Positive Stop feature on driveline outputs eliminates oil seal damage from coupling over-travel. Reference documents: 281/288 Series Parts List (HY25-2281-M1/US) and the 267/281/288/871/878 Series Owner's Manual are available from Parker Chelsea.
Parts Manual: Chelsea 281 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
