Mobile Power Tipline: Pumps GPM PSI

Pumps: Flow and Pressure

How do you determine what size hydraulic pump is need for your specific application?

First determine with the body manufacturer, what flow (GPM) is necessary for operation, and what the system’s max operating pressure (PSI) needs to be.

Sizing your Pump

Muncie Power Products uses pumps that are generally rated at 1000 pump shaft RPM.

To determine what your pump shaft RPM will be, multiply your engine RPM by your PTO speed percentage. For example: a truck running the engine at 1200RPM with a PTO speed percentage of 112% will have a pump shaft RPM of 1344RPM. Using this example with a Muncie pump rated for 15GPM, you would see approximately 20GPM.

Always be sure to have the correct size hoses on your pump, and never bush down of constrict the flow on the suction/inlet side. Doing so will potentially starve the pump for oil and cause it to burn up.

Understanding Pressure Limitations

The pump itself does not generate pressure. The pump is rated to withstand a specific pressure, generated by the system itself. Over pressurization of the pump/system can cause cavitation in the pump and cause failure. A pressure relief valve is a valuable tool in preventing this occurrence.

Note: It is important t avoid using Teflon tape on Muncie Power Products pumps, or any other brand. The use of Teflon tape will void any warranty considerations.

You can find more information on Muncie pumps on Muncie’s website, or by calling R&M Equipment Company at 610-495-9706.

Mobile Power Tip Line: Stud Kits

Stud Kits – an often overlooked aspect to PTO installation

Correct stud kit installation is essential to PTO operation and ensuring long life. Failure to follow correct stud kits installation could result in leaks and PTO/transmission damage.

6 & 8 Bolt Installation

Install the stud until the barrel of the stud is even with the transmission pad. This typically requires a torque limit of 30-35 lbs.-ft. (6 bolt pad) or 40-45 lbs.-ft. (8 bolt pad). If more torque is required to install the stud to the barrel or to the depth shown in the table below, remove the lock patch form the stud and transmission mounting holes and use a liquid Loctite in place.


Place the shims/gaskets over the installed studs. Position the PTO and start the nuts. Do not tighten yet. Check for gaps and proper mesh between gear teeth. Check for proper backlash. Tighten and torque using the “X” pattern. Torque mounting cap screws/nuts to 40-45 lbs.-ft. (6 bolt) or 50-55 lbs.-ft. (8 bolt).

CS24 & CS25 Bolt Installation
Install alignment studs in transmission housing the correspond with the following diagram.

stud-kits-in95-02The mounting gasket on the installed studs. Check for gaps/proper mesh between gear teeth. Assure correct installation of Nordlock washers on the correct cap screws; tighten top and bottom cap screws.



Tighten remaining screws using “X” pattern. Torque 40-45 lbs. ft.stud-kits-image-3

You can find information on correct stud kit installation in the owner’s manual provided with you PTO, on Muncie’s website, or by calling R&M Equipment!