Overview
The ZF 2095.073.002 TRA 13 is an OEM genuine internal clutch piston assembly engineered for the high-torque planetary gear sets within ZF’s heavy-duty transmission range. This component functions as the hydraulic actuation interface, converting oil pressure into linear force to engage or disengage specific gear ratios. Positioned directly inside the transmission drum, the TRA 13 piston is critical for maintaining precise clutch pack clamping force during load cycles. The SKU 2095.073.002 designates a factory-sealed unit manufactured to ZF’s original tolerances, ensuring consistent shift quality under extreme construction machinery loads.
Symptoms of Failure
When the ZF 2095.073.002 piston wears or cracks, operators will notice distinct operational degradation. Below are the most common failure indicators:
- Delayed or harsh engagement: A worn piston seal causes hydraulic pressure loss, resulting in a 2-3 second lag when shifting from neutral to drive under load.
- Internal transmission oil leaks: Cracks in the piston body allow pressurized ATF to bypass the clutch pack, visible as puddling around the bell housing or a persistent low-fluid warning.
- Intermittent gear slipping under load: As the piston fails to hold full clamping force, the transmission slips out of gear when climbing grades or lifting heavy payloads.
- Metallic debris in oil pan: Fragments from a fractured piston surface contaminate the hydraulic circuit, often found during routine filter inspections.
Technical Specifications
| Parameter | Value |
|---|---|
| Part Number | 2095.073.002 |
| Designation | TRA 13 (Piston Assembly) |
| Material | High-tensile aluminum alloy with nitrile sealing ring |
| Outer Diameter | 180 mm (7.09 in) |
| Inner Diameter | 95 mm (3.74 in) |
| Height | 42 mm (1.65 in) |
| Weight | 0.85 kg (1.87 lbs) |
| OEM Reference | ZF 2095.073.002 (Genuine) |
| Operating Pressure | 12–18 bar (174–261 psi) |
Compatibility
This TRA 13 piston is specifically designed for ZF’s modular transmission families used in construction machinery. It directly fits the following models:
- ZF WG180 (6-speed powershift, used in wheel loaders)
- ZF WG200 (heavy-duty variant for excavators and dozers)
- ZF 4WG-200 (4-speed version with integrated torque converter)
- ZF 6WG-250 (high-torque off-highway transmission)
Always verify your transmission’s serial number against the ZF parts catalog before installation. For cross-reference, this piston replaces earlier revisions 2095.073.001 and 2095.073.000.
