Features
Hydraulic PowerShift (hot-shift) operation for 10-bolt automatic transmission apertures, commonly Allison
Ductile iron bearing cap - 117% stronger than gray iron for increased durability
O-ring sealing configuration between housing and bearing cap reduces vibrational effects and improves clamp load
Enhanced clutch pack with steel discs 80% thicker than the predecessor to resist premature tooth wear
Nine speed ratios including low and high speeds
Electronic Overspeed Control (EOC) protects driven equipment; SmartStart reduces shock load at start-up
Wet spline lubrication option provides 7 to 10 times greater shaft life; rotatable cast-iron flanges reduce interference clearance issues
Tech Specs
- Mounting Type: 10-Bolt aperture
- Shift Type: Hydraulic PowerShift (hot-shift)
- Transmission Compatibility: Allison automatic transmissions
- Continuous Operation: Yes
- Series Continuous Torque Rating: 390 lb-ft (529 Nm) - see application pages for actual torque ratings
- Speed Ratios: Nine, including low and high speeds
- 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
- Lubrication: Pressure lube or wet spline options
- Markets: Fire and rescue, truck cranes, refuse, pumper-cleaner
Additional Information
The Chelsea 281 Series is documented in the 281/288 Series Parts List (HY25-2281-M1/US) and the 267/281/288/871/878 Series Owner's Manual. Rotatable cast-iron flanges reduce pump clearance interference, and the positive-stop feature on driveline outputs eliminates oil seal damage from coupling contact. The optional SmartStart round output shaft (1-1/4 in. with 5/16 in. key) reduces shock load at engagement, making this series a practical choice for cycling applications in fire apparatus and refuse equipment.
Parts Manual: Chelsea 281 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
