The Chelsea 890 Series Power Take-Off, part number 890MFFJW-B5AF or 890MFFJWB5AF, is a hydraulic hot-shift PTO engineered for Allison 3000 MD and 4000 HD Series transmissions. The 890 Series mounts via a 10-bolt pattern with an additional rear-of-transmission support bracket, positioning the SAE C output flange at the rear of the transmission to create adequate clearance for the pump. The one-piece main shaft eliminates the input splines found in PTO-plus-extension configurations, and the clutch is located at the rear of the housing so the gear section sits tight against the transmission. Wet spline lubrication protects the output shaft and pump drive splines under demanding duty cycles. Continuous torque rating reaches 670 ft-lb; intermittent torque exceeds 501 ft-lb. Shaft power output is 64 HP at 500 RPM and 128 HP at 1,000 RPM. Typical applications include aerial trucks, fire and rescue, refuse, and truck crane service. Call us to confirm proper fit for your specific Allison transmission configuration.
Features
Fits Allison 3000 MD and 4000 HD Series transmissions via 10-bolt mounting
Hydraulic PowerShift (hot-shift) engagement
SAE C ("XS") output flange and output shaft type
One-piece main shaft eliminates PTO-to-extension input splines for added durability
Wet spline output lubrication extends PTO and pump shaft life in high-demand applications
Continuous torque rating up to 670 ft-lb; shaft power 64 HP at 500 RPM and 128 HP at 1,000 RPM
Tech Specs
- Transmission Application: Allison 3000 MD and 4000 HD Series
- Product Series: 890
- Mounting Type: 10-Bolt (with additional rear-of-transmission support bracket)
- Shift Type: Hydraulic PowerShift (hot-shift)
- Outlet Flange Type: SAE C
- Output Shaft Type: SAE C ("XS") Output
- Continuous Torque: 670 ft-lb (check application pages for actual torque ratings)
- Intermittent Torque: 501+ ft-lb
- Output Power: 56+ HP (51+ kW)
- Shaft Power: 64 HP (48 kW) at 500 RPM; 128 HP (95 kW) at 1,000 RPM
- Lubricant/Spline Type: Wet Spline
Additional Information
The Chelsea 890 Series is built specifically for applications where pump clearance and high torque capacity are critical requirements. Unlike a PTO-with-extension arrangement, the 890 Series is a single unit with a one-piece main shaft, removing the input spline joint between the PTO body and the output extension. The clutch assembly is positioned at the rear of the PTO housing, allowing the gear section to mount flush against the transmission and move the pump output flange rearward, fitting between the transmission and the frame rail. This geometry suits aerial trucks, fire and rescue pumpers, refuse trucks, and truck crane applications where available mounting space is limited and sustained high-torque output is required. The wet spline output technology keeps the drive splines lubricated under continuous-duty cycling, reducing wear on both the PTO output and the mating pump shaft. The 890 Series accommodates Allison transmissions equipped with or without a cooler, a retarder, or both.Parts Manual: Chelsea 890 Series PTO Parts Manual (PDF) — exploded views, item numbers and the full parts breakdown for this series.
