Power Take Off: All You Need to Know

This article was updated March 2025

Road planers, dredges, rock crushers, woodchippers, and other equipment require power from some type of engine to perform their designed function. Without a power take-off, it would be difficult for these machines to be as robust and capable as they are.

The power take-off (PTO) is not simply just a practical addition, it is a valuable element providing crucial functions. Recognizing their value requires a better understanding of these systems, their various types, and their diverse applications.

Understanding Power Take-Offs

Power take-offs allow mobile crushing plants, road milling machines, and other equipment to transfer engine power to perform primary and auxiliary functions. A PTO is a device (a mechanism) usually seated on the flywheel housing, which transfers power from the engine to a secondary application.

In most cases, this power transfer is applied to a secondary shaft or belt system that drives a hydraulic pump, generator, air compressor, pneumatic blower, vacuum pump, chipper disc, crusher drum, or fan.

Selecting the Right PTO

PTO choice is critical to providing sufficient power to the equipment without severely limiting the main function of the prime mover. Selection of a power take-off requires specific information relating to the application and the power needs of the secondary or driven component(s).

Here is a quick list of considerations for PTO selection:

Torque, power, and speed of the engine
Intermittent or continuous operation
SAE flywheel housing and flywheel sizes
Method of PTO engagement
Drive configuration (belt or shaft)
Space allocation
Application usage

Having these specifications available makes the proper selection of a PTO a simple task.

PTO Torque and Horsepower Requirements

Torque, power, and speed of the engine are among the most critical specifications in the list above. Knowing this information is essential for optimal performance.

In most cases, this information can be found on the engine specification sheet or data label affixed to the engine. Once you have this information, determining the recommended torque capacity for the PTO is a relatively straightforward calculation using the formula below:

RTC = Rated Engine Torque x SF

RTC (recommend torque capacity) is the calculated input torque capacity required from the PTO. SF (service factor) is the ratio between the PTO’s rated input and the engine’s rated output and is based on the application. It ranges from 1.5 for light-duty to 1.75 for medium-duty and 2.0 and above for heavy-duty applications. Please consult WPT Power for details on selecting the proper service factor.

If you do not know the rated torque output of the engine, you can estimate the value using the horsepower (HP) and speed of the engine using the formula below:

RTC = (HP x SF)/RPM x 5252

HP is the rated engine power. RPM is the speed of the engine at the rated power.

Keep in mind that these calculations are estimates and should only be used to provide tentative selections. For a complete application review and guidance, please get in touch with WPT Power Applications Engineering.

The Different Types and Industrial Applications of PTO Clutches

Though they perform the same general function—transferring power from the primary drive to a secondary drive shaft for a driven component—there are various PTO types available that serve specific industrial applications. These diversifications are why WPT Power supplies OEM’s units in agricultural, energy, forestry, and road building sectors, among others.

Pilotless® Mechanical PTO

The distinguishing characteristic of this type of PTO is the intentional removal of the pilot bearing. The benefits of this design feature come with an increased side load capacity, reduced inventory, increased uptime and engine life, and a quicker, easier installation. This PTO can be used in inline or sideloaded setups and features the time-tested lever-actuated mechanical over-center clutch.

Industrial applications of the Pilotless® Mechanical PTO include:

Chippers
Rock crushers
Pump jacks
Water blasters
A wide variety of other heavy-duty Road Building & Construction machines

Mechanical PTO

This type of flywheel PTO is a staple in the industry. It includes a sealed-for-life pilot bearing and utilizes the same lever-actuated manual clutch as the Pilotless. The benefit of this type of PTO is compatibility with existing units.

This type most commonly applies to:

Engine packages
Irrigation pumps
Barge pumps
Hand-fed wood chippers

Type 1 PTO

This is a rugged, high-capacity power take-off used in a broad range of industrial functions. The main characteristic of this type of PTO is the sheave mounted between two heavy-duty spherical roller bearings. This design is engineered to attain the maximum potential of the bearings in full load situations.

Among the most common applications for the Type 1 PTO are:

Type 2 PTO

The design of the Type 2 PTO features a heavy-duty side loading capacity using sizeable spherical roller bearings. The actuation of this PTO can be configured either hydraulically or pneumatically. It is self-adjusting and removes the need for the pilot bearing inside the engine flywheel. Features include reduced maintenance, less chance of premature failures, and improved engine and bearing life since there is no direct loading to the crankshaft.

Common applications for Type 2 PTOs include:

Road building equipment (milling machines, stabilizers)
Portable rock crushers
Tub grinders

Type 1 vs. Type 2 PTO Clutches

The difference between these two PTO clutch types is their varied functional designs.

Type 1 PTOs include 2 to 4 times the side load capacity of a Type 2 PTO, so they best suit heavier, belt-driven, industrial applications with high-impact loading.
Type 2 PTOs allow for high-capacity loading in a smaller footprint and are best for light-to-medium capacity side loading.

Pilotless® Over-the-Shaft PTO

This PTO design eliminates the need for the pilot bearing while providing increased side loading and hydraulic or pneumatic actuation in an inline application. Its engineering accommodates the most demanding requirements of high-loading diesel engines. Features include simple installation, reduced downtime, and improved engine service life. This style of PTO has the hydraulic/pneumatic fittings mounted on the bell housing instead of at the rear of the shaft like the Type 1 and Type 2.

GM® Style PTO

The GM Style PTO reduces maintenance time and cost by using sealed main bearings and eliminating the need for a pilot bearing or bushing. Designed to mount directly to GM® style engines, these operate without the need for any particular PTO or engine adaptations. Notable features include clutch adjustments using an external ball stud and a high-capacity version for belt-driven setups.

Common applications for the GM-stye include:

Irrigation pumps
Sawmills
Wood chippers

Automotive Style PTO

Also known as “flat-faced” style PTOs, they incorporate similar design characteristics, features, and benefits of the GM-style PTO. It is a spring-loaded clutch, making it easier to engage and disengage than over the center power take-offs.

Typical uses include:

Irrigation units, brush chippers
Engine packages
Other gas or diesel engine applications

Common Operational PTO Clutch Problems and Solutions

PTOs are relatively simple mechanical units with minimal operational problems. There are a few common issues, but each has a straightforward solution. Here are some of the most frequently encountered issues:

The clutch will not disengage. Slipping and overheating are common causes of these issues and are fixable by disassembling, inspecting, and replacing if necessary. To prevent this type of problem, be sure to check and adjust the engagement torque often.
The clutch will not stay engaged. Improper adjustment is the most common cause, remedied through adjusting engagement torque.
PTO is hot. A newly installed PTO will run hot for the first 10 to 20 hours of operation after installation. Several issues contribute to overheating (220º F measured by an infrared thermometer at the bearing carrier), including too much or too little grease, excessive sideload, or a new installation. Follow proper lubrication specifications and reduce the sideload to remedy the first two problems.

Get a Quality PTO to Meet Your Needs at WPT Power

Delivering a quality PTO to meet your operational needs is a priority at WPT Power. That is why our PTO manufacturing and engineering takes place in our ISO 9001:2015 facilities. Here, all our products are designed to meet the highest standards of quality demanded by our customers.

In-house testing facilities and certification, including ABS, DNV, and ATEX, help to minimize risks, time, and costs.

Unmatched Customer Service, Sales, and Engineering

Our unmatched customer service, sales, and engineering are what set us apart from our competition. The friendly, knowable WPT staff are available without all the phone menu options and department shuffling that has become standard with these larger companies. When you call for technical questions, application design, or to place an order, you talk to a real person. It’s as simple as that.

Global Markets and Service

WPT serves many types of markets globally, including:

We also have an extensive network of knowledgeable distributors to ensure that your product needs will be met quickly and with minimum downtime – when and wherever you are, worldwide.

Custom or Modified OEM Solutions

Our broad range of products has been developed to meet most of the requirements for standard industrial applications. Custom or modified PTOs are available for original equipment manufacturers (OEM) requiring specialized design and where volume is needed.

WPT’s sales and engineering teams work directly with the OEM engineering team to design a solution to meet the application requirements. If you don’t see a standard WPT product that fits your application, please contact us today to discuss custom solutions.

More Information

Power take-offs play an essential role in allowing for the transfer of power from a primary mover to a secondary or driven. Various PTO types serve many applications, from smaller-scale operations to major industrial and construction projects. Choosing the correct PTO for a specific application is critical to the proper performance of the driven component.

Contact us for more information about the range of solutions offered by WPT Power Corporation, for assistance in selecting the right PTO to fit your specific application, or request a quote from one of our experts.