ZF PowerLine 8 Speed Automatic Transmission

The ZF PowerLine 8, also marketed under various derivative names, is an 8 speed automatic transmission designed and manufactured by ZF for the medium and heavy duty truck segments. Its first and most prominent applications in the domestic 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 (for both progressive and regressive shifts), torque converter lockup in first gear, and a vibration dampening torque converter.

Ram TorqueFlite HD

Ram adopted the PowerLine transmission for the 2025 model year and it is standard on all trucks equipped with the 6.7 liter Cummins High Output Turbodiesel, including the Ram 3500, 4500, and 5500 chassis cabs. It is marketed as the TorqueFlite HD 8 speed transmission, although it is also listed as the 8AP1075 in some technical data. This designation could be deciphered as 8 speed automatic, PTO equipped, 1,075 lb-ft maximum input torque capacity.

Rumors about Ram adopting the ZF built 8 speed transmission for their heavy duty pickup trucks began circulating as early as 2018. These rumors were largely substantiated in 2024 when ZF began investing heavily in domestic production. Additionally, in a press release dated February 6th, 2024, ZF claimed to be ramping up production for the PowerLine 8 to "satisfy demand from U.S. commercial vehicle manufacturers, including three U. S.-based customers."

One might argue that Ram was in desperate need of a powertrain upgrade after its competitors began offering 10 speed automatic transmissions in their diesel powertrain configurations. The 8 speed's two extra gears may not seem all that significant, but the addition brings the average gear step from 44% to 34%, as compared to the outgoing Aisin 6 speed transmission. It also offers a significantly deeper, industry leading 4.89 to 1 first gear ratio which translates to significantly more available torque when starting from a stop; the greater torque multiplication at low speeds can prove especially beneficial when towing heavy trailers.

Transmission Specs

[1] - ZF rates the input torque capacity at 1,000 lb-ft, PACCAR lists the rating as high as 1,050 lb-ft, and the 6.7 Cummins variant has at least a 1,075 lb-ft rating
[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.
[4] - Specifically for Ram truck applications
[5] - Fluid capacity will vary by application - 2 wheel drive vs 4 wheel drive, for example

Features

• Dual simultaneous 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)

Gear Ratios

Gear Steps

Comparison - AS69RC, 10L1000, 10R140