Cross-Reference Turbocharger K03 7256748 – Fits Bobcat S750 T770

Verified Variant Fitment — each K03 turbocharger cross-referenced against Bobcat serial ranges to prevent flange-angle mismatches before the unit ships.

Technical Specifications

Application Suitability

Why the Same Turbocharger Part Number Ships in Multiple Variants

The suffix letter on a Doosan D34 turbocharger determines whether it bolts on or sits on the shelf.

I have watched crews in the Pearl River Delta unbox a K03 turbocharger for a Bobcat S770 only to find the exhaust flange rotated just far enough off to prevent a seal. The part number 150105-00344 looked correct on paper. In reality, the variant suffix — C, E, or G — governed the flange clocking, and the cross-reference table everyone copied from had not been updated since the earlier production run. That machine sat idle while a replacement was air-freighted across the country [NEED_CITE: aftermarket cross-reference accuracy in compact equipment turbo applications].

The same base number may correspond to several physical configurations across Bobcat A770 through T870 models. Production batches shifted oil port placement, gasket surface dimensions, and compressor housing orientation without changing the core reference. Mechanics relying on a worn nameplate or a secondhand parts catalog are essentially guessing, and the cost of a wrong turbocharger extends well beyond the return freight.

Serial Range Verification Across the Bobcat Compact Line

Fitment for this turbocharger for Bobcat S750 T770 and the wider compact track loader range depends on matching the machine serial against the correct Doosan D34 build variant. The S740 through S850 skid steer series and the T740 through T870 track loader series share the same engine platform, but the turbocharger mounting configuration changed across production years. Providing the full machine serial number — not just the model badge — allows the technical team to narrow down which of the several cross-reference numbers applies to a specific unit.

Flange Geometry, Oil Port Position, and Gasket Surface

The physical interface between turbocharger and engine block determines whether installation proceeds smoothly or requires field modification — which is never acceptable on a pressurized intake system. Key checkpoints include the exhaust inlet flange bolt spacing relative to the manifold stud pattern, the oil drain port diameter and clocking angle, and the compressor outlet orientation relative to the charge air piping. Even a minor difference in gasket surface finish between variants can cause a boost leak that triggers derate codes on the D34 ECU [NEED_CITE: turbocharger mounting interface tolerance standards for off-highway diesel engines]. Before any bulk commitment, dimensional photos or a sample unit allow side-by-side comparison with the removed turbocharger.

Reading the Cross-Reference Chain Without Inheriting Errors

Part number 5303-970-0458 appears in many aftermarket catalogs as a direct swap for 7256748, and in some cases that is correct — but not across every Bobcat serial range. The BorgWarner K03 family carries its own numbering system (5303-970-xxxx and 5303-988-xxxx series) that maps to specific OEM configurations. When a superseded number has been replaced, the new reference may govern a different oil restrictor size or wastegate calibration. Double-directional verification — working forward from the old number and backward from the proposed replacement — catches transcription errors that propagate through copied tables.

Interpreting K03 Turbo Specifications for Field Performance

The K03 turbocharger is sized for the Doosan D34 displacement and power band between 74 and 100 HP, meaning the compressor map is calibrated for the airflow demand typical of compact loaders working at sustained high load. The turbine aspect ratio governs spool response — a smaller ratio delivers faster boost buildup from idle, which matters when a skid steer cycles between travel and digging every few seconds. Wastegate calibration controls maximum boost pressure; a unit calibrated for a different power output will either over-boost (risking head gasket failure) or under-boost (triggering ECU derate). Oil feed and drain port sizing must match the D34 lubrication circuit pressure, because an undersized drain line causes oil pooling in the bearing housing and eventual seal failure [NEED_CITE: turbocharger oil drain sizing guidelines for industrial diesel engines]. These parameters are not adjustable in the field, which makes getting the correct variant at the ordering stage essential.

The Cost of Installing a Close-But-Wrong Turbocharger

A turbocharger that physically bolts on but carries the wrong variant suffix does not simply underperform — it fails early and takes adjacent components with it. A slightly misaligned exhaust flange leaks hot gas onto nearby wiring harnesses and hydraulic lines. Incorrect wastegate calibration forces the engine to run outside its intended air-fuel envelope, accelerating piston ring wear and increasing exhaust gas temperatures beyond what the downstream aftertreatment system was designed to handle. The second repair always costs more than the first, and the machine owner rarely realizes the root cause was a parts lookup error rather than a quality defect [NEED_CITE: root cause analysis methodology for turbocharger-related engine failures].

Why Buyers Source This Turbocharger Through XUNPO

Own production on selected lines and qualified sourced supply operate under one account and one warranty, so a replacement K03 turbocharger for Bobcat S750 T770 carries the same quality terms regardless of which line it came from. Eight product categories allow a complete repair — turbocharger, gasket set, oil feed line, air filter — to ship as a single consignment from the Guangzhou warehouse. Minimum order is one piece, so a workshop replacing a single failed unit faces no quantity barrier. The technical team verifies fitment from a machine model, serial number, or nameplate photograph, and cross-reference checks cover superseded numbers that other sellers may have dropped from their listings. A sample unit can be dispatched for trial fitment before a distributor commits to a bulk order, removing the guesswork from variant selection.

Documentation & Verification

• Commercial invoice and packing list referencing all cross-reference numbers on the order
• Turbocharger compatibility and cross-reference sheet marked as reference only for each listed number
• Dimensional inspection record covering flange bolt pattern, oil port spacing, and housing clocking
• Warranty terms covering manufacturing defects for 3-12 months from delivery
• Pre-dispatch packing photographs showing unit condition and protective packaging
• HS code and customs classification support for international shipment

Fitment Check Before Installation

• Compare exhaust inlet flange bolt hole spacing against the removed turbocharger before mounting
• Verify oil drain port clocking angle matches the engine block return line orientation
• Check compressor outlet direction against existing charge air pipe routing
• Inspect gasket mating surfaces for flatness and finish match with manifold
• Confirm wastegate actuator bracket alignment with the mounting stud on the exhaust manifold
• Trial-fit without gaskets first to verify clearance around adjacent frame members and heat shields

Requesting a Fitment Confirmation

Send the full machine model and serial number from the Bobcat data plate, or a clear photograph of the existing turbocharger nameplate if the reference number is still legible. If the nameplate is worn or painted over, a photo of the exhaust flange and oil port arrangement is usually sufficient for the technical team to identify the correct variant. For distributors planning a stock order across several Bobcat models, provide the model and serial list to receive a consolidated compatibility matrix before committing quantities.

Frequently Asked Questions

Q: How do I confirm this turbocharger fits my Bobcat S750 or T770? A: Provide the full machine serial number from the data plate. The same model badge can span several production years with different Doosan D34 engine builds, each requiring a specific turbocharger variant. The technical team cross-references the serial against known configuration records and returns the confirmed part number within hours, along with dimensional photos for your comparison.

Q: My old unit shows 5303-970-0458 — is that still available? A: That BorgWarner reference maps to the K03 family and corresponds to one or more Doosan and Bobcat part numbers in this cross-reference chain. Some earlier numbers have been superseded by updated references with revised specifications. Share a photo of the old nameplate along with your machine serial, and the team will confirm the current available reference that matches your specific configuration.

Q: What is the difference between 150105-00344 suffixes C, E, and G? A: Each suffix designates a production variant with differences in flange orientation, oil port placement, or compressor housing clocking. Installing the wrong suffix on a Bobcat S770 or T770 can result in exhaust leaks or oil line interference. Verification against the machine serial number is required to identify which suffix applies to your specific unit.

Q: The nameplate is unreadable — can I still get the right turbocharger? A: Yes. A clear photograph of the turbocharger housing showing the exhaust flange, oil ports, and compressor outlet is usually sufficient for identification. Combined with the Bobcat model and engine serial from the machine data plate, the technical team can confirm the correct K03 variant without relying on the worn label.

Q: Can I order one sample before placing a bulk order? A: Single-piece samples are available for fitment verification before any volume commitment. This is especially useful for distributors stocking across multiple Bobcat models, allowing physical trial installation on a representative machine to confirm flange geometry, port alignment, and clearance before the full order ships.