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Need a new Stanadyne DB2 or DB4 injection pump for a John Deere, Caterpillar or Perkins engine? This guide matches the right new pump to your engine by part number, and helps you decide when a brand-new unit beats rebuilding your old core. The DB2 and its higher-pressure successor the DB4 are among the most widely used rotary distributor pumps ever built — Stanadyne calibrated the same pump dozens of different ways, so the specification number is what settles the match. Below are the exact new pumps we stock by application, the symptoms that mean yours is done, and a straight answer on new vs. rebuild. (Already know you want to rebuild your core instead? Jump to our Stanadyne DB2 & DB4 rebuild guide.)
What the DB2 and DB4 actually are
Both are mechanical, opposed-plunger rotary distributor pumps: a single pumping element feeds every cylinder in turn through a rotating distributor, instead of the bank of individual plungers you find in an inline pump. That design made them compact, affordable and tolerant of the duty an ag tractor or a generator sees. The DB4 is the later, higher-pressure evolution used on newer and larger engines. Stanadyne calibrated the same basic pump dozens of different ways for John Deere, Caterpillar, Perkins, GM, Ford and a long list of industrial and marine builders — which is exactly why the specification number matters more than the model name.
Signs your DB2 or DB4 is failing
- Hard starting or long cranking, hot or cold — worn transfer-pump blades or a tired hydraulic head lose the pressure needed to fire quickly. (Rule out a cold-only issue with our diesel cold-start problems guide first.)
- Power loss and a lower top RPM under load, as internal leakage robs fuel delivery.
- Surging or hunting that will not settle — often a governor or automatic-advance issue. The injection pump timing symptoms can look identical, so it is worth confirming.
- Diesel weeping from the throttle shaft, top cover or housing seals.
- Fuel in the governor housing, or a pump that has ingested water or contaminated fuel — a leading killer of the hydraulic head.
- White smoke and rough running from uneven or retarded delivery.
Because these are old pumps on hard-worked engines, a “bad pump” complaint is sometimes a lift-pump, filter or air-intrusion problem instead. Before condemning the pump, confirm clean, water-free fuel — a fresh quality fuel filter protects the pump you are about to pay for — and, if you have the gauges, verify transfer pressure before condemning the pump.
DB2 and DB4 applications and part numbers
These are the specific new Stanadyne pumps we stock and the John Deere, Caterpillar and Perkins engines they are built for. Read the Stanadyne DB number and the OEM number off your pump tag — either one lets us confirm the exact match.
| Stanadyne P/N | Type | Engine / Application | OEM Ref |
|---|---|---|---|
| 06322 | Rotary | John Deere 4045D & 4045T (4.5L) | DE2435-6322 |
| 06323 | Rotary | John Deere 4045H (4.5L) | DE2435-6323 |
| 06237 | Rotary | John Deere 6068H (6.8L) | RE557897 |
| 02802 | DB2 | John Deere 4219D & 4219T | AR15747 |
| 02731 | DB2 | John Deere 4202D | AR69819 |
| 05214 | DB4 | Caterpillar & Perkins 1004-40T | 1627500 |
Do not see your exact number? The DB2 and DB4 were fitted to far more equipment than any table can list. Read the tag on your pump and we will confirm the right unit — new or rebuilt — before you buy the wrong part.
New vs. rebuild: how to decide
Both paths end with a pump that runs to specification. The right choice comes down to your core, your timeline and availability.
A brand-new pump makes sense when…
- You need the machine back now and cannot wait on a core exchange.
- Your old pump is seized, cracked or badly contaminated — if the core is not rebuildable, a rebuild is off the table.
- You do not have the old pump at all (bought the machine without it, or it is already gone).
- The new price lands close to the rebuild once you factor downtime — common on the high-volume 4045 pumps.
A rebuild of your core makes sense when…
- Your pump is a good, rebuildable core and you want the most economical route.
- Your exact number is no longer manufactured new — common on older DB2 and DB 310 applications.
- You want the pump calibrated to your engine’s exact spec sheet and proven on a bench before it ships.
We do both under one roof. Every rebuild is torn completely down, inspected against Stanadyne factory wear limits, deep-cleaned, rebuilt with factory-certified parts and calibrated on a computer-controlled Stanadyne test bench — then backed by a 1-year warranty. The full process, cost range and turnaround live in our Stanadyne DB2 & DB4 rebuild guide; when you are ready to send your core in, start the DB2, DB4 & DB 310 rebuild service.
John Deere is the most common application
Most Stanadyne pumps we ship go onto John Deere ag and industrial engines — the 4045 (4.5L) and 6068 (6.8L) especially. If your Deere is hard-starting, down on power or surging, work through the specific failure patterns in our John Deere injection pump problems guide before ordering, then match the number to the table above. Running a Yanmar-built Deere or a compact instead? The rotary-pump symptoms overlap closely with Yanmar injection pump problems.
How to identify your pump
Every DB2 and DB4 carries a Stanadyne data tag stamped with the model (DB2, DB4) and a specification number. John Deere equipment also has a John Deere number — an AR, RE or DE prefix — on the tag or in your parts book. Any one of those numbers lets us confirm the exact unit. If the tag is painted over or unreadable, give us the engine model and serial and we will work it from the application side. Browse the full lineup on our diesel injection pumps page, or call with your number and we will match it — new or rebuilt — before you spend a dime.
Frequently asked questions
What is the difference between a Stanadyne DB2 and a DB4?
The DB4 is the later, higher-pressure evolution of the DB2 rotary distributor design, used on newer and larger engines such as the CAT/Perkins 1004-40T. Both share the same opposed-plunger architecture; the DB4 supports higher injection pressures and updated internals.
Which Stanadyne pump fits my John Deere 4045?
It depends on the variant: the 4045D and 4045T use Stanadyne 06322 (DE2435-6322), the 4045H uses 06323 (DE2435-6323), and the 6.8L 6068H uses 06237 (RE557897). Confirm against the number on your pump tag or your John Deere parts book before ordering.
Should I buy a new pump or rebuild my old one?
Buy new when you need the machine back immediately, when your core is seized, cracked or contaminated beyond rebuild, or when you no longer have the old pump. Rebuild your core when it is good, when you want the most economical route, or when your exact number is no longer manufactured new. We offer both.
Do you ship Stanadyne injection pumps nationwide?
Yes. We ship new Stanadyne pumps anywhere in the country with free UPS Ground to the lower 48, and we rebuild cores mailed in from anywhere. Valley Fuel Injection has been a certified diesel fuel injection shop since 1993.
