Genuine Kubota Common Rail Assembly 1J770-50604 (RAIL,ASSY)

Part number 1J770-50604 is the genuine Kubota common rail assembly, Kubota catalog description RAIL,ASSY, for the V3307-CR family of 3.3 liter common rail diesel engines. It fits Kubota SVL75-2 and SVL65-2 compact track loaders, SSV75 and SSV65 skid steers, KX057-4 and U55-5 excavators, R Series wheel loaders, and M4 series tractors running the V3307-CR engine. The rail is the high pressure heart of the fuel system: it stores fuel at injection pressure from the supply pump and feeds all four injectors, so a contaminated, damaged, or leaking rail can take down the entire system. Valley Fuel Injection is an authorized Kubota dealer, and we sell this rail as a genuine new Kubota part, verified against your engine serial number before it ships.

A note on supersession: Kubota part records show 1J770-50604 in the chain 1J770-50600 to 1J770-50603 to 1J770-50604, with 1J770-50605 listed as the current replacement. If Kubota has rolled your order to the newest number, we supply the current genuine rail and confirm the interchange for your engine before anything ships.

Application & Fitment

This rail assembly is confirmed for the Kubota V3307-CR common rail engine family, including the V3307-CR-TE4 and V3307-CR-T-EF04. Several listings also show the same rail used on V2607-CR engines; we treat that as probable rather than certain, and we will confirm it against your engine serial number before you buy.

Confirmed equipment applications include:

• Kubota SVL65-2, SVL65-2C, SVL75-2, SVL75-2C compact track loaders
• Kubota SSV65, SSV65C, SSV75 skid steer loaders
• Kubota KX057-4 and U55-5 excavators
• Kubota R530, R530CA, R540, R630, R630CA, R640 wheel loaders
• Kubota M4-071HDC12 and M4D-061HDC12 tractors

Not sure which rail your machine needs? Call us with the serial number off the engine block and we will pull the exact part record before you spend a dime.

Cross-Reference Part Numbers

• Denso 095600-5360 (rail manufacturer number shown in listings for this part)
• Kubota 1J770-50600 and 1J770-50603 (earlier numbers replaced by 1J770-50604)
• Kubota 1J770-50605 (current supersession of this number)

Frequently Asked Questions

Has 1J770-50604 been superseded?

Yes. Kubota lists 1J770-50605 as the current replacement for 1J770-50604, and the numbers interchange on the same applications. When you order from us you get the current genuine Kubota number, matched to your engine serial number, so there is no guesswork about whether the newer rail fits your machine.

Do I need a new rail, or just injectors?

It depends on why the system failed. After a fuel contamination event, debris from a failing supply pump or bad fuel travels through the rail and into every injector, and reusing a contaminated rail is the fastest way to ruin a fresh set of injectors. Our shop performs common rail system repair in house and can test your injectors and supply pump, so call before you buy parts and we will help you scope the job honestly.

Is this a genuine Kubota part?

Yes. Valley Fuel Injection is an authorized Kubota dealer, and this listing is for a genuine new Kubota rail assembly in Kubota packaging, not an aftermarket copy. On a component that holds fuel at tens of thousands of PSI, genuine is the only version we are willing to stand behind.

Why do I see this part cheaper online?
Short answer: it is usually not the same part — and it takes the fuel system with it. Read why ↓

Search any OE number and eBay, Amazon and a dozen storefronts will show it well under dealer cost, sold by outfits with no name, no address and no phone number. We lose business to those listings every week — and we see a lot of them come back through our shop. Here is what is actually different.

• The part number proves nothing on its own. Counterfeit injectors and pumps are stamped with the same OE numbers as the real thing, in housings cast to look identical. The number in the listing title tells you what the seller claims it is, not what came off an OE line.
• “Remanufactured” is not a regulated word. A genuine reman unit is stripped to bare components, has its wear parts replaced — nozzle, plunger and barrel, solenoid, seals — and is then run on a calibration bench until it meets the original flow and response spec. A cheap one is very often cleaned, resealed, painted and shipped. Both get called remanufactured.
• No full teardown, so no idea what is worn. A proper rebuild means the unit comes apart completely and every part gets inspected and measured against spec — not just the ones that are obviously bad. Skip the teardown and you are reusing worn internals inside a freshly painted housing. It will run on the truck. It will not last.
• No factory-spec bench load testing. A unit is not finished until it has been run under load on a test bench and made its numbers across the range, not just at one easy point. That bench time is most of what you are paying for. Sellers working on price cut it first, because nobody can see it in a photo.
• The warranty has to be honored by someone. Everything we remanufacture in house carries a one-year warranty, with 30 days on electrical components. Parts we supply as an authorized dealer carry the manufacturer’s own warranty. Either way you call us, a real shop in California, and we sort it out. A marketplace warranty usually means shipping the part overseas at your own cost and hoping for a reply.
• No core program. We credit your rebuildable core back in full. Discount sellers generally will not take one, so the gap narrows the moment you account for the core you are now stuck holding.
• Rail-side failures contaminate everything downstream. A rail or sensor that was never validated can strand the truck or send debris through the injectors. On a common rail system, the cheap part is rarely the expensive mistake — the fuel system it takes with it is.

We are an authorized dealer and a working fuel-injection shop — we have been rebuilding and testing this hardware in Woodland since 1993, and the people who answer the phone are the people who run the benches. Not sure this is the right part for your engine? Call us with your serial number before you order and we will confirm it. Send your rebuildable core back and the core charge is refunded. And if a price somewhere else looks too good, call 530-668-0818 and we will tell you straight whether it is a deal or a problem.

Why Buy From Valley Fuel Injection

We have been diesel fuel injection specialists in Woodland, California since 1993, and we are an authorized dealer for Kubota engines, parts, and service. We do not just sell the rail. Our shop lives in diesel fuel injection service every day, so the person who answers the phone can tell you whether a rail, injectors, or a supply pump is the right fix for your machine.

Call for Pricing

Call 530-668-0818 for current pricing and availability on Kubota common rail assembly 1J770-50604, or contact us online. Have your engine model and engine serial number ready so we can verify fitment and quote the correct current part number the first time.