ZF PowerLine 8 Automatic Transmission

The ZF PowerLine 8, also marketed under various derivative names, is an 8 speed automatic transmission designed and manufactured by ZF for medium duty truck applications. Its first and most prominent applications in the United States market include PACCAR produced trucks sold under the Kenworth and Peterbilt brands. PACCAR began offering the transmission in its medium duty truck lines for the 2023 model year and markets the transmission as the "PACCAR PowerLine TX-8". The transmission boasts a range of highly sophisticated features including automatic hill control, neutral idle control, "skip shift" shifting (in both up and down shifts), torque converter lockup in first gear, and a vibration dampening torque converter.

Ram Rumored to Adopt 8 Speed ZF Transmission

The rumors of Ram Trucks adopting a ZF built 8 speed automatic transmission for their heavy duty pickups is not all that new. In fact, these rumors began circulating as early as 2018. Fast forward to 2024, and we actually have a few hints to substantiate the claims. We now know that ZF has invested heavily in expanding operations at their Gray Court, SC assembly site, which is actively producing and delivering PowerLine 8 model transmissions. Additionally, in a press release dated February 6th, 2024, ZF claimed to be ramping up production of the PowerLine 8 to "satisfy demand from U.S. commercial vehicle manufacturers, including three U.S.-based customers."

While ZF doesn't go into specific details on their U.S. based clientele, we already know that PACCAR began using the PowerLine 8 speed automatic transmission in their 2023 model Kenworth and Peterbilt branded medium duty trucks. Is PACCAR one of the three U.S. based customers, or do the Kenworth and Peterbilt model lines count as two individual U.S. based customers? Regardless, Ram may very will be included as one of the three vehicle manufacturers contributing to a higher demand for the PowerLine transmission.

One might say the Ram HD platform is in desperate need of a powertrain upgrade. While the mighty H.O. Cummins Turbodiesel pleases with its brute strength, Ram limits its 3/4 ton customers to a significantly lesser powered version of the engine. And although the Aisin AS69RC offers equally impressive durability, the 6 speed transmission may be holding the Cummins back. Even die-hard Cummins fans who have experienced the Ford and GM 10 speed configurations can appreciate the seamless confidence these transmissions deliver as they effortlessly step through gears while pulling substantial loads.

Two extra gears may not seem all that significant, but the addition pair of gears brings the average gear step from 44% to 34%, as compared to the current Aisin 6 speed. It also offers a significantly deeper, industry leading 4.89 to 1 first gear ratio compared to the Aisin's 3.72, which will translate to significantly more available torque when starting from a stop; the Cummins Turbodiesel doesn't need more power, but the greater torque multiplication at low speeds would be a substantial benefit. We sincerely hope that the PowerLine transmission does land in the Ram HD platform, giving rise to an even more formidable competitor.

ZF PowerLine 8 Transmission Specs

[1] - ZF rates the input torque capacity at 1,000 lb-ft, but PACCAR lists the rating as high as 1,050 lb-ft. For the transmission to survive in a Ram 6.7 Cummins application, the torque capacity would need to exceed 1,000 lb-ft.
[2] - Based on current PACCAR applications; ZF suggests 26,000 lbs GVWR.
[3] - Transmission has dual PTO capability in stationary and mobile operation, but not every variation is equipped with a dual PTO package nor is compatible in mobile operation; actual PTO layout is application specific.

ZF PowerLine 8 Transmission Ratios

Gear Steps

Additional Transmission Features

• Dual power take-off capability in stationary and mobile operation
• Torque converter lockup available in first gear
• Neutral idle control feature shifts transmission into neutral under certain coasting conditions to conserve fuel
• "Skip shift" shift schedule finds the right gear for the prevailing conditions
• Hill-hold function helps resist rolling when starting from a standstill on a grade
• Ability to start in 1st or 2nd gear as determined by the prevailing conditions
• Specifically designed for class 5 to 8 medium and heavy duty trucks
• Transmission mounted oil cooler (mounted beneath rear case cover)

Comparisons - AS69RC, 10L1000, 10R140