Features
Ductile iron bearing cap rated 117% stronger than gray iron
O-ring sealing configuration between housing and bearing cap improves clamp load and resists vibrational effects
80% thicker steel discs in the clutch pack to resist premature tooth wear
Nine speed ratios including low and high speeds
Rotatable cast-iron flanges reduce pump clearance interference
Wet Spline Lubrication option provides 7 to 10 times greater shaft life
SmartStart feature reduces shock load at start-up for select applications
Electronic Overspeed Control (EOC) protects driven equipment
Tech Specs
- Mounting Type: 10-Bolt
- Shift Type: PowerShift (Hydraulic Hot-Shift)
- Transmission Compatibility: Allison automatic transmissions (10-bolt aperture)
- Continuous Torque: 390 lb-ft (529 Nm) - see application pages for actual ratings
- Intermittent Torque: 301 to 400 lb-ft (501+ Nm)
- Output Power: 56+ HP (51+ kW)
- Shaft Power: 37 HP at 500 RPM / 74 HP at 1000 RPM (28 kW at 500 RPM / 55 kW at 1000 RPM)
- Output Types: SAE B Pump Flange, SAE C Pump Flange, ISO 7652 Pump Flange, Driveline
- Output Shaft Options: SmartStart Round Shaft (1-1/4 in. with 5/16 in. key), 3/4 in. 11T Pump Spline, SAE B 7/8 in. 13T Pump Spline, SAE C 1-1/4 in. 14T Pump Spline, DIN 5462 Pump Spline, 1410 Companion Flange, DIN 120 Flange, DIN 100 Flange
- Lubrication: Pressure Lube or Wet Spline options
- Speed Ratios: Nine ratios including low and high speeds
- Continuous Operation: Yes
- Typical Markets: Fire and Rescue, Truck Cranes, Pumper Cleaner, Refuse
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. Additional factory publications include the 281 Series Sales Literature and service notices PTO-PNI-292 covering the 281, 288, 871, and 878 Series. These documents cover assembly, service intervals, and application-specific torque ratings.
Parts Manual: Chelsea 281 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
