Because of the large physical size of the pumps used on oil field exploration and maintenance trucks, clearance has always been a challenge. Chelsea’s new 899 Series was designed with this in mind to provide maximum clearance for the 4700 Series transmissions. Another challenge is the torsional vibrations from today’s diesel engines that prematurely wear out mating PTO and pump splines. The Wet Spline System that lubricates the mating PTO and Pump shafts will increase the life of these components 7 to 10 times longer than a dry mating connection. The 899 features six speed ratios, eight output types and is a constant mesh shifter which is an excellent option for variable displacement piston pump applications.