890 Series

The Chelsea 890 Series Power Take-Off (PTO) is a hydraulic hot shift unit designed specifically for Allison 3000 and 4000 series transmissions, delivering industry-leading performance with torque capacity up to 670 lb-ft. Engineered for applications where space and power are critical, it provides improved clearance by fitting neatly between the transmission and the truck frame rail, while positioning the pump output toward the rear for optimal packaging. Unlike extension-style configurations, the 890 Series is a single integrated unit featuring a one-piece main shaft that eliminates intermediate input splines between the PTO and output section. This design improves strength, reduces wear points, and enhances long-term durability. The clutch assembly is positioned at the rear of the unit, allowing the housing and gear section to sit closer to the transmission for a more compact installation. The 890 Series also incorporates Wet Spline Technology on the output, helping extend PTO and pump shaft life in high-demand operating conditions. It can be specified for transmissions with or without coolers, retarders, or both, offering broad installation flexibility. Designed for the most demanding vocational applications, the Chelsea 890 Series PTO is widely used in aerial equipment, fire and rescue vehicles, snow and ice service trucks, defense applications, and other mobile equipment where high torque and tight installation space are required.