The Chelsea 281GBFJP-S5RK is a 281 Series hydraulic PowerShift (hot-shift) power take-off engineered for automatic transmissions with a 10-bolt aperture, including Allison and Caterpillar applications. The 281 Series carries a continuous torque rating of 390 lb-ft and is built for continuous-duty operation across demanding markets including fire and rescue, refuse, truck cranes, and pumper cleaner equipment. Key structural improvements over the predecessor 280 Series include 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 clutch pack steel discs increased 80% in thickness to resist premature wear. Nine speed ratios are available, including low and high-speed options. Output configurations span SAE B and SAE C pump flanges, ISO 7652 pump flange, and driveline. A genuine Chelsea part, available from Pro Gear and Transmission.
Features
Hydraulic PowerShift (hot-shift) operation for use during live transmission engagement
10-bolt mounting aperture for Allison and Caterpillar automatic transmissions
390 lb-ft continuous duty torque rating
Ductile iron bearing cap, 117% stronger than gray iron predecessor
Clutch pack steel discs increased 80% in thickness over 280 Series for reduced premature wear
O-ring sealing between housing and bearing cap improves clamp load and reduces vibrational effects
Tech Specs
- Mounting Type: 10-Bolt
- Shift Type: PowerShift (Hydraulic) / Hot Shift
- Continuous Torque: 390 lb-ft (529 Nm)
- Continuous Operation: Yes
- Transmission Compatibility: Allison and Caterpillar automatic transmissions (10-bolt aperture)
- Output Types: SAE B Pump Flange, SAE C Pump Flange, ISO 7652 Pump Flange, Driveline
- Speed Ratios: Nine available (includes low and high-speed)
- Shaft Power: 37 HP at 500 RPM / 74 HP at 1000 RPM
Additional Information
The 281 Series is an evolution of the Chelsea 280 Series PTO. Structural upgrades include a ductile iron bearing cap (117% stronger than the gray iron cap used in the 280 Series), an o-ring sealing configuration between the housing and bearing cap, and clutch pack steel discs 80% thicker than the prior design. These changes target reduced vibration damage associated with modern engine designs. A wet spline lubrication option is available within the 281 Series and provides 7-10 times greater shaft life compared to standard lubrication. Electronic Overspeed Control (EOC) is a series feature that protects driven equipment from overspeed events. Rotatable cast iron flanges allow pump clearance adjustment at installation. SmartStart reduces shock load at start-up for applicable configurations. Relevant Parker Chelsea 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.
