ZF 4HP 16 Automatic Transaxle
The ZF 4HP 16 is a 4-speed automatic transaxle designed for cars with front-wheel
drive and with a transversely mounted engine.
The transaxle has a hydrodynamic torque converter with a controlled slip lockup
clutch.
A planetary gear train establishes the mechanical gear ratios. The integral
constant ratio can be adapted to the engine power output and the vehicle weight. The
electronic-hydraulic control makes controlled power shifts and various shift programs
possible. In Park position, the output is locked mechanically.
The ZF 4HP 16 transaxle operates without freewheels. Shifting between individual
gears occurs using overlapping clutch engagement and release.
Overlap shifting provides the following advantages:
| • | The transaxle is a more compact design and lighter because of the absence
of freewheels and the lower number of shift elements. |
| • | The transaxle reduces the drag losses, resulting in higher efficiency. |
| • | A lower number of peak torques acting on the components and driveline. |
However, overlap shifting requires high-performance hardware and software and
precision engine signals.
Notice: Lack of basic knowledge of this powertrain when performing diagnostic
procedures could result in incorrect diagnostic performance or damage to powertrain
components. Do not attempt to diagnose a powertrain problem without this basic
knowledge.
The ZF 4HP 16 automatic transaxle consists primarily of the following
components:
Mechanical
| • | A torque converter with TCC |
| • | Two multiple disk clutch assemblies: Clutch B, E |
| • | Three multiple brake assemblies: Brake C, D, F |
| • | Two planetary gear sets |
| • | A final drive and differential assembly |
Electronic
| • | Two shift solenoid valves: 1, 2 |
| • | Four pressure control solenoid valves |
| • | Two speed sensors: A/T ISS and A/T OSS |
| • | A fluid temperature sensor |
| • | An automatic transaxle control module (TCM) |
| • | A wiring harness assembly |
