Features
Hydraulic (PowerShift) hot-shift design for 10-bolt automatic transmission apertures, commonly Allison
Ductile iron bearing cap, 117% stronger than gray iron predecessor
Enhanced clutch pack with 80% thicker steel discs to resist premature tooth wear
O-ring sealing configuration between housing and bearing cap improves clamp load and reduces vibrational effects
Nine speed ratios including low and high speeds; 390 lb-ft continuous torque rating (series-rated)
Wet Spline Lubrication option provides 7 to 10 times greater shaft life; 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 Rating: 390 lb-ft / 529 Nm (series-rated; verify application-specific rating)
- Continuous Operation: Yes
- Speed Ratios: Nine, including low and high speeds
- Output Types: SAE B Pump Flange, SAE C Pump Flange, ISO 7652 Pump Flange, Driveline
- Lubrication: Pressure Lube or Wet Spline option
- Electronic Overspeed Control (EOC): Available
Additional Information

Related Parker Chelsea documentation: 281/288 Series Parts List (HY25-2281-M1/US); 267/281/288/871/878 Series Owner's Manual; 281 Series Sales Literature. Contact Pro Gear and Transmission for assistance identifying the correct PTO configuration for your transmission and application.
Parts Manual: Chelsea 281 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
