Rear-mount PTOs in North America
Power take-offs (PTO) have long been a critical part of the vocational truck industry, providing the necessary power to allow nearly every hydraulic truck application to do the work at hand. Historically, in North America, most truck applications utilize side-mounted PTOs on transmissions following the Society of Automotive Engineers’ (SAE) standard 6-bolt and 8-bolt apertures.
Today, however, we continue to see significant change in how PTOs are mounted, including unique transmission specific 10-bolt mounting apertures from manufacturers—such as Allison and Ford—as well as apertures on the top, bottom, and rear sections of some transmissions.
The rear-mount PTO has long been a standard on European style trucks and is commonly used on applications in that market. Until recently, rear-mount PTOs were few and far between in North America, but have now begun to build some traction as more European manufacturers enter the market and bring their preferred mounting style.
Rear-mount PTOs, also known as countershaft PTOs, are attached to the rear of the transmission and are driven by the countershaft, instead of meshing with a transmission gear. While still more uncommon in North America, rear-mount PTOs do provide some advantages: easier installation due to less interference, higher torque limits, and more compatibility with DIN pump options.
Today, there are numerous transmissions available in the North American market with the rear-mount option including:
Detroit Diesel DT12 Transmission
The DT12 transmission is commonly used on Freightliner or Western Star Class 8 Cascadia or 5700 trucks. This transmission requires the 362-822 Detroit PTO prep kit option. Muncie Power offers the RS6S-P89M PTO which is designed specifically for this transmission and features an integral hydraulic mount for structural support of hydraulic pumps up to 60 lbs. without additional transmission support. The RS6S-P89M is capable of different ratios, several different outputs, and the ability to mount larger displacement pumps.
The Mack mDrive and mDrive HD transmissions are automated manual transmissions that are standard on Mack Pinnacle, Mack Granite, and Titan by Mack trucks. These chassis must be ordered with the PTO prep package. Muncie Power offers multiple PTO options for these transmissions including the RS4S-P81, RS4S-P86, and RS4S-P93 each with a max torque exceeding 360 ft.lbs. that can be configured for either driveline or direct mount pumps applications.
The Volvo I-SHIFT transmissions are automated manual transmissions available for all Volvo trucks including the VNR, VNL, VNX, VHD, and VAH model options. These chassis must be ordered with the PTO prep package as well. Muncie Power offers multiple PTO options for these transmissions including the RS4S-P81, RS4S-P86, and RS4S-P93 each with a max torque exceeding 360 ft.lbs. that can be configured for either driveline or direct mount pumps applications.
There are other older transmission models with the rear-mount option still in the marketplace, as well as numerous other options internationally, but side-mount PTOs still dominate North America. We will continue to see a slow rise in rear-mount PTOs in the North American marketplace; therefore, it’s important to know which transmissions offer the option and when it makes sense to use it to your advantage.
