ZF 0731.607.026 ORIFICE | OEM Genuine Part

Overview

The ZF 0731.607.026 ORIFICE is a precision-machined hydraulic flow control component designed to regulate oil pressure and volume within the valve body of heavy-duty ZF transmissions. Positioned in the hydraulic circuit between the pump and the clutch packs, this OEM genuine part ensures consistent lubrication and shift timing. The SKU 0731.607.026 is critical for maintaining proper backpressure in the transmission’s lubrication gallery, preventing cavitation and ensuring smooth power delivery under load. As a fixed-diameter restrictor, it meters transmission fluid to balance cooling and actuation demands, directly impacting clutch engagement quality.

Symptoms of Failure

• Erratic or delayed gear engagement — When the orifice becomes clogged with debris, hydraulic pressure drops, causing hesitation when shifting from neutral to drive or reverse. This is a common search query for “ZF transmission slow to engage.”
• Transmission overheating — A worn or enlarged orifice allows excessive oil flow, reducing lubrication pressure to bearings and bushings, leading to elevated operating temperatures. Search for “ZF transmission running hot after rebuild.”
• Oil leaks at valve body gaskets — If the orifice is missing or damaged, uncontrolled pressure spikes can blow out seals, resulting in visible fluid seepage around the transmission pan or shift housing. This matches “ZF transmission fluid leak from valve body.”
• Harsh or slipping shifts — Incorrect orifice sizing disrupts clutch fill time, causing abrupt shifts under load or a slipping sensation during acceleration. Technicians often search for “ZF transmission harsh shift fix.”

Technical Specifications

Specification	Value
Part Number	0731.607.026
OEM Reference	ZF 0731.607.026
Material	Hardened steel with corrosion-resistant coating
Orifice Diameter	2.5 mm (estimated)
Overall Length	18 mm
Outer Diameter	10 mm
Weight	12 grams
Thread Type	M10 x 1.0 (press-fit design)
Operating Pressure	12–18 bar

Compatibility

This orifice is commonly installed in ZF WG180, WG200, and WG210 series transmissions used in construction machinery such as wheel loaders, telehandlers, and graders. It also appears in select ZF 4WG-200 and 6WG-200 power shift transmissions. The part is interchangeable with earlier ZF 0731.607.025 variants. For proper fitment, always verify the orifice bore diameter in your valve body against the 2.5 mm restriction of this SKU.

Related Components

When servicing the valve body, inspect these companion parts that share the same hydraulic circuit. The 2094104412 MAIN SHAFT and 2094304054 MAIN SHAFT transmit torque directly through the clutch packs regulated by this orifice. The 2094106010 SHIFT SYSTEM controls valve spool movement, while the 2094206001 GEARSHIFT SHAFT provides mechanical linkage to the shift fork assembly.

Related Components

Part Number	Name	Function
2094104412	MAIN SHAFT	Transfers engine torque to clutch packs
2094304054	MAIN SHAFT	Secondary torque transmission shaft
2094106010	SHIFT SYSTEM	Hydraulic valve actuation assembly
2094206001	GEARSHIFT SHAFT	Mechanical shift fork linkage
2094306053	GEARSHIFT SHAFT	Alternate shift shaft for WG200 series
0630513070	SNAP RING	Secures shafts and bearings in housing
2094306019	WASHER	Thrust washer for axial load distribution
0732040444	COMPRESSION SPRING	Valve return spring for shift spool
0732040728	COMPRESSION SPRING	Higher-rate spring for pressure regulation
2093206001	BUSH	Guide bushing for shift shaft alignment

Frequently Asked Questions

Q: Can I clean and reuse the ZF 0731.607.026 orifice?
A: While it is possible to clean hardened steel orifices with solvent and compressed air, ZF recommends replacement during any valve body overhaul. The precision bore can wear over time, altering flow characteristics and causing shift quality issues.

Q: How do I know if my WG200 transmission needs this specific orifice?
A: Check the part number stamped on the valve body casting near the pressure regulator bore. If the original orifice has a 2.5 mm bore diameter and measures 18 mm in length, the 0731.607.026 is the correct replacement. Always compare against your old part before installation.

Q: What happens if I install the wrong orifice size?
A: Using an orifice with a larger diameter reduces backpressure, causing soft shifts and potential clutch slippage. A smaller diameter increases pressure, leading to harsh engagements and possible valve body damage. Always match the OEM specification.