The Chelsea 878 Series Power Take-Off Assembly, part number 878XDFJP-M5RY or 878XDFJPM5RY, is a constant mesh PTO engineered for Allison and CAT 10-bolt transmissions. The 878 Series improves on the proven 877 Series platform with a ductile iron bearing cap rated 117% stronger than gray iron, an O-ring sealing configuration between the housing and bearing cap to reduce vibrational effects and improve clamp load, and an 80% increase in clutch pack disc thickness. The series carries a 670 lb-ft continuous torque rating and offers nine speed ratios spanning low and high ranges. Rotatable cast-iron flanges reduce interference clearance issues, and driveline outputs include a positive stop to eliminate oil seal damage. Hose is included. Applications span refuse, vacuum, aerial, and snow and ice equipment. Call us to confirm proper fit for your specific transmission.

The 878 Series is Chelsea's evolution of the 877 Series PTO, sharing the same 10-bolt Allison and CAT mounting footprint while adding structural and sealing improvements. Markets served include refuse trucks, vacuum trucks, aerial equipment, and snow and ice vehicles. The part number SP878XDFJP-M5RY may appear as a cross-reference in some catalog listings for this same assembly. For fitment questions or to verify this unit matches your transmission, contact Pro Gear and Transmission directly.
Features
Ductile iron bearing cap, 117% stronger than gray iron, to resist vibration from modern engine designs
O-ring sealing configuration between housing and bearing cap improves clamp load and reduces vibrational effects
Single continuous duty torque rating of 670 lb-ft (series rating) eliminates the need to derate for continuous operation
Nine speed ratios available, including low and high speeds
Rotatable cast-iron flanges reduce interference clearance issues
Wet Spline Lubrication option extends shaft life 7 to 10 times compared to standard; hose included
Tech Specs
- Shift Type: Constant Mesh
- Mounting Type: 10-Bolt (Allison and CAT transmissions)
- Continuous Torque Rating (series): 670 lb-ft (908 Nm) - check application pages for actual torque rating
- Speed Ratios: Nine ratios, including low and high speeds
- Output Shaft Options (series): SAE B (7/8 in. - 13T) Pump Spline, SAE BB (1 in. - 15T) Pump Spline, SAE C (1-1/4 in. - 14T) Pump Spline, DIN 5462 Pump Spline, 1410 Series Companion Flange, DIN 120 Flange, DIN 100 Flange
- Output Flange Options (series): SAE B Pump Flange, SAE C Pump Flange
- Continuous Operation: Yes
- Lubrication: Pressure Lube or Wet Spline options available
- Hose: Included
Additional Information

The 878 Series is Chelsea's evolution of the 877 Series PTO, sharing the same 10-bolt Allison and CAT mounting footprint while adding structural and sealing improvements. Markets served include refuse trucks, vacuum trucks, aerial equipment, and snow and ice vehicles. The part number SP878XDFJP-M5RY may appear as a cross-reference in some catalog listings for this same assembly. For fitment questions or to verify this unit matches your transmission, contact Pro Gear and Transmission directly.
Parts Manual: Chelsea 878 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
