The 890 Series Power Take-Off (PTO) for Allison 3000/4000 transmissions is mounted between the transmission and the frame rail of the truck. It mounts like a standard side-mounted PTO with an additional bracket at the rear of the transmission, and places the output of the PTO beyond the rear of the transmission where there is extra space. The 890 Series is a single unit, not a PTO with an extension. The main shaft is one piece, eliminating the input splines between the PTO and the shaft extension. The clutch has been moved to the rear of the unit to allow the housing and gear section to tuck in tightly to the transmission. The output utilizes a wet spline, which eliminates fretting problems.