DEF Pump Filter Kit for Caterpillar Tier 4 - Replaces 301-3897 - OEM Quality Filter Element

DEF Pump Filter Kit — Protect Your DEF System

The DEF Pump Filter is the first line of defense for your SCR emissions system. It filters the Diesel Exhaust Fluid (urea) before it reaches the DEF dosing injector. When this filter clogs with crystallized DEF or contaminants, it starves the dosing injector — causing it to fail prematurely.

Why This Filter Matters

Every time a DEF dosing injector fails, the root cause is usually a dirty pump filter. Contaminated DEF passes through the clogged filter and crystallizes inside the injector nozzle. Mechanics replace the $500+ injector — but forget the $45 filter. Then the new injector clogs within months.

Don't make this mistake. Replace the filter every time you replace the dosing injector.

What's Included

• Genuine Bosch DEF pump filter element
• O-ring seals for proper sealing
• Installation is straightforward — locate the DEF pump, remove the filter housing cap, swap the element, and reinstall

Technical Specifications

• Cat Part Number: 301-3897
• Manufacturer: Bosch (Germany)
• Bosch Part Number: 1 457 436 033
• Type: DEF Pump Inline Filter Element
• Condition: Brand New, Genuine OEM

Compatible Equipment

Fits all Caterpillar Tier 4 Interim and Final machines equipped with the Bosch Denoxtronic 2.2 emissions system, including:

• Cat 320E/F, 323E/F, 324E, 329E/F, 336E/F, 349E/F Excavators
• Cat 950K/M, 962K/M, 966M, 972M Wheel Loaders
• Cat 12M, 140M, 160M Motor Graders
• Cat D6T, D7E, D8T Dozers

Why Buy From Trenchwell?

• Save 47% vs Dealer: Cat dealers charge $85+ for this filter kit. We sell the identical Genuine Bosch part for $45.
• Free Shipping: Small, lightweight item — we ship it free to make this an easy add-on to your order.
• Don't Skip This: A $45 filter protects your $589 dosing injector. It's the cheapest insurance you can buy for your emissions system.