The ZF PowerLine 8, also marketed under various derivative names, is an 8 speed automatic transmission designed and manufactured by ZF Friedrichshafen AG 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.
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 engine, 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 moving heavy trailers.
Transmission Specs
| Manufacturer | ZF Friedrichshafen AG | |
|---|---|---|
| Designation(s) | TorqueFlite HD, 8AP1075, ZF PowerLine, ZF PowerLine 8, PACCAR PowerLine TX-8, PowerLine 8AT, PowerLine 8AP | |
| Type | 8 speed automatic transmission, rear wheel drive | |
| Predecessors | Chrysler 68FRE & Aisin AS69RC | |
| Applications | 2025 - 2027 Ram 2500, 3500, 4500, 5500 (pickup truck and chassis cab) 2023 - current Peterbilt & Kenworth medium duty trucks (various) |
|
| Production Plant | ZF Gray Court Transmission Plant, Gray Court, South Carolina | |
| Overall Ratio (Ratio Spread) | 7.65 | |
| Gear Ratio Range | 4.89 - 0.64 | |
| Average Gear Step | 34% | |
| Control Type | Electronic | |
| Position Quadrant | P, R, N, D | |
| Torque Converter | Twin torsional damper torque converter | |
| Max Input Torque | > 1,075 lb-ft [1] | |
| Max GVWR | 33,000 lbs [2] | |
| Max GCWR | 57,000 lbs | |
| Case Material | Cast aluminum | |
| Pan Material | Composite | |
| Weight | 328 lbs dry, 364 lbs with oil | |
| PTO Provisions | Stationary and mobile PTO capabilities [3] | |
| PTO Locations | 3 o'clock passenger side, 9 o'clock driver side | |
| PTO Flange | 8 bolt | |
| Max PTO Output | Single, stationary | 516 ft-lbs |
| Single, mobile | 258 ft-lbs | |
| Dual, stationary | 738 ft-lbs in combination | |
| Dual, mobile | 516 ft-lbs in combination | |
| Service Interval | 60,000 miles, 48 months [4] | |
| Fluid Type/Spec | MOPAR 818 automatic transmission fluid ZF-Lifeguard Hybrid 2 synthetic ATF (AT818) |
|
| Fluid Capacity | 17.96 U.S. quarts [5] | |
| Sump Filter | MOPAR 68720332AA - filter and gasket are integral to fluid pan [6] | |
| Pan Gasket | ||
[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.
[6] - Transmission fluid pan features integral gasket and sump filter; serviced as one assembly, not as individual parts.
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 | Ratio (:1) |
|---|---|
| 1st | 4.890 |
| 2nd | 3.123 |
| 3rd | 2.033 |
| 4th | 1.639 |
| 5th | 1.254 |
| 6th | 1.000 |
| 7th | 0.840 |
| 8th | 0.639 |
| Reverse | 4.250 |
Gear Steps
| Shift Sequence | Step |
|---|---|
| 1st to 2nd | 57% |
| 2nd to 3rd | 54% |
| 3rd to 4th | 24% |
| 4th to 5th | 31% |
| 5th to 6th | 25% |
| 6th to 7th | 19% |
| 7th to 8th | 31% |
Editor, Diesel Hub