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Caterpillar 3P-4002 is the hydraulic gear pump in a black cast iron body with a round mounting flange, splined drive shaft and a flanged outlet elbow. It is used on Caterpillar D8H and D9G bulldozers. This aftermarket version is made to the same mounting and connections as the original, so it fits where the old one came off.
Sold as one unit. Check the number on your old part, or in the parts manual for your machine, before ordering.
| Part Type | Hydraulic Gear Pump |
| Replaces | Caterpillar 3P-4002 |
| Machine | Caterpillar D8H, D9G bulldozers |
| Fits | Caterpillar D8H and D9G bulldozers |
| Condition | New, aftermarket |
| Stat. HS-Code | 841360 |
| Country of Manufacture | China |
Caterpillar machines
Check the part number on your old unit before ordering.
| Caterpillar Part No.(SPM Part No.) | Fits |
|---|---|
| 3P-4002(SPM-HEP-5075) | Caterpillar D8H and D9G bulldozers |
| 3P4002(SPM-HEP-5075) | Caterpillar D8H and D9G bulldozers |
Slow or weak hydraulics
A worn pump loses flow and pressure: functions slow down, especially when the oil is hot.
Noise
Whining or knocking from the pump points to worn gears or pistons, or cavitation from a blocked suction line.
Contamination
Metal in the filter or oil means the pump is wearing. Replace it before debris damages valves and motors.
Fitting tips
Flush the system, change the oil and filters, fill the pump case before starting, and run at low speed first.
We check what other aftermarket sellers charge for this same part. Their prices on the date we checked:
| Seller | Price | Checked |
|---|---|---|
| eBay, aftermarket seller | USD 276.36 | 2 Nov 2026 |
| Kudu Parts | USD 337.00 | 2 Nov 2026 |
| Buy Machinery Parts | USD 352.98 | 2 Nov 2026 |
| FridayParts | USD 370.63 | 2 Nov 2026 |
| SINOCMP | USD 529.00 | 2 Nov 2026 |
| Spare Part Mart | USD 221.09 | Today |
Our price of USD 221.09 is 20% to 58% less than these sellers.
Found this part cheaper somewhere else? Send us the listing and we will beat it by 5% under our Price Beat Guarantee. Every order is also covered by our 30 day money back guarantee.
Yes, it was made for the Caterpillar D8H, and 1 more listed under compatible equipment. Check the old hydraulic pump is marked 3P-4002 or one of the cross references, because makers change parts between serial ranges.
On the Caterpillar D8H, often 5,000 to 10,000 hours with clean fluid, much less with dirt or air in the system. It is usually changed on condition, not by hours.
Leaks from the seal or weep hole, noise or whining, overheating, or falling pressure or flow under load.
Yes. Fill the pump and its suction line with clean fluid before the first start. Running it dry, even for a few seconds, can score it.
Clean them right back to metal and fit the new gasket or O-ring dry, unless the engine manual calls for sealant.
No. It is an aftermarket hydraulic pump made to replace the Caterpillar 3P-4002. It is not made by the original manufacturer; the number only shows what it replaces.
Live rates for the quantity selected, delivered to your door. Confirmed at checkout.
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