Overview
The ZF 4699.825.187 GP25 is a genuine OEM gearset assembly engineered for the high-torque planetary stages of ZF construction machinery transmissions. This part, identified by SKU 4699.825.187, functions as the primary power transfer unit within the gearbox, converting rotational input from the engine into controlled output for the driveline. It sits directly in the main shaft cluster, interfacing with the clutch packs and housing to manage load distribution under heavy excavation and loading cycles. As a GP25 variant, it is precision-machined to maintain tight backlash tolerances, ensuring smooth engagement during directional shifts.
Symptoms of Failure
- Grinding noise during gear engagement: A distinct metallic grinding sound when shifting from forward to reverse indicates worn gear teeth on the 4699.825.187 assembly.
- Intermittent power loss under load: If the transmission slips or fails to hold torque when climbing grades or lifting heavy loads, the GP25 gearset may have pitting or spalling on the contact surfaces.
- Metallic debris in transmission fluid: Finding silver or bronze particles on the magnetic drain plug or in the oil filter signals advanced wear of the 4699.825.187 gearset.
- Oil leaks near the main housing seam: Excessive vibration from a failing GP25 can loosen adjacent seals, leading to fluid seepage around the HOUSING interface.
Technical Specifications
| Parameter | Specification |
|---|---|
| Part Number | 4699.825.187 |
| Type | GP25 Gearset Assembly |
| Material | Case-hardened alloy steel (20MnCr5) |
| Weight | 8.4 kg (18.5 lbs) |
| Outer Diameter | 195 mm |
| Tooth Count | 25 (sun gear) / 72 (ring gear) |
| OEM Reference | ZF 4699.825.187 |
| Heat Treatment | Carburized & quenched to HRC 58-62 |
Compatibility
This GP25 gearset is designed for use in ZF WG180, WG200, and WG210 series powershift transmissions commonly found in wheel loaders, telehandlers, and graders. It is also compatible with the 4WG-200 and 6WG-200 variants used in heavy construction machinery. For proper installation, ensure the 4699025039: GP25 companion gear is inspected for wear. The assembly mates directly with the INPUT shaft and the OUTPUT flange, requiring precise alignment to prevent premature failure.
Related Components
| Part Number | Name | Function |
|---|---|---|
| 4699025039 | GP25 | Matched gearset for torque distribution |
| 4699101113 | HOUSING | Encloses gearset and supports bearings |
| 4699102157 | INPUT | Drives the GP25 from the torque converter |
| 4699103114 | OUTPUT | Transfers power to the differential |
| 4699109068 | BRAKE PARTS | Friction discs for holding the gearset |
| 4699301201 | HOUSING | Secondary housing for clutch pack |
| 4699309202 | HOUSING COVER | Seals the gearset cavity |
| 0636101477 | CAP SCREW | Fastens housing to transmission case |
| 0631302221 | CYLINDRICAL PIN | Aligns gearset during assembly |
| 0501319149 | SCREW PLUG | Seals oil passages in the housing |
