What This Turbo Does
The HX40W is a single-stage exhaust-driven charger bolted to the exhaust manifold flange on the 8.3L 6C-platform engine. Exhaust gas spins the turbine wheel, the shaft drives the compressor wheel, and intake air gets pressurized into the charge cooler. Lose that and you lose boost, power and fuel economy all at once, usually with black smoke on throttle.
This aftermarket unit uses cast compressor and turbine housings machined to factory flange dimensions, so the exhaust inlet, V-band and oil feed and drain locations match the original layout. The rotating assembly is dynamically balanced as a cartridge, which is what keeps the shaft from walking under load and eating the bearings.
Applications are industrial, bus and medium-duty. Cummins lists this family across 6CTAA, 8.3CTAA and ISC 8.3L builds, 2002 and later Tier 2. That covers a lot of serial ranges, which is exactly why the engine serial number matters more than the model name on the valve cover.
Why These Numbers Cross
3598263, 4089321, 3598715 and 4036628 all sit in the same Holset HX40W service family for the 8.3L 6C platform. Turbo part numbers in this family change when the supersession chain moves, when a wastegate actuator spec is updated, or when a housing is released under a new assembly number — not because the core turbo became a different turbo.
What holds the cross together is the hard geometry: turbine housing flange pattern and A/R, compressor cover outlet, CHRA bearing housing, and oil feed and drain porting. Those are common across the group, so a unit built to 3598263 physically lands where any of the others came off.
Where they can differ is actuator calibration and clocking. A charger set up for one chassis may have the compressor housing rotated to clear a different intake elbow, and wastegate can pressure can vary by application. Both are checkable on the old unit before you commit.
Check Before You Order
Pull the tag off the old turbo and read the number stamped on it. That number, plus your engine serial number, is what confirms the swap. A cross-reference list gets you into the right family — it does not confirm fitment on your specific unit. Verify by ESN or by the number on the part you removed.
Before you condemn the turbo, check the obvious: restricted air filter, collapsed intake boot, plugged charge cooler, and a blocked oil drain line. A coked drain line will kill a new charger in short order. Also inspect the exhaust manifold for cracks, and check shaft end play and radial play by hand.
When you install, prime the bearing housing with clean oil, use new gaskets on both flanges, and idle the engine two or three minutes before loading it. Note the clocking and actuator rod length on the old turbo so the replacement goes back the same way.
3598263 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3598263. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| Cummins/Holset | 4089321, 3598715, 4036628 |
Frequently asked questions
Will a turbo listed as 3598263 replace 4089321 on my 8.3?
They fall in the same HX40W service family for the 8.3L 6C platform, so the flange geometry and CHRA are shared. That makes it a strong starting point, not a guarantee. Compare the tag on the removed unit and confirm against your engine serial number before ordering.
Why is my new turbo leaking oil out the compressor side?
On a fresh install that is almost always a drain-side problem, not a seal problem. A restricted or kinked oil drain line, a plugged crankcase breather, or high crankcase pressure will push oil past the seal ring. Check drain flow and crankcase pressure before pulling the charger back off.
Does the wastegate actuator come set from the factory?
Actuator rod length and can pressure are set for the application the unit is built to. Measure the rod length and note the mounting position on your old turbo before removing it, then compare on the replacement. If the geometry differs, sort it out before the turbo goes on the manifold.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
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Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.