HX55 4089754 Turbocharger for Cummins ISX Signature 450

HX55

The HX55 (4089754 / 4036892) is the Holset fixed-geometry turbocharger for the Cummins ISX1 and ISX Signature 450 engine, a 15.0L Class 8 powerplant used in Freightliner, Kenworth T660/T800/W900, and other over-the-road trucks from 2004-2011. This is a non-EGR, non-wastegated, twin-scroll turbo — mechanically simple, with no electronic components. It is a different turbo from the HX55 (3536995) used on the smaller M11/ISM 10.8L engine. Same turbo model name, different internals sized for the 15.0L ISX. Our HX55 is built new with all new components, dynamically balanced, and ships with gaskets. We supply shops, fleets, and distributors.

Turbo Model

HX55 (fixed geometry, non-wastegated, twin-scroll)

OEM / Interchange Numbers

4036892, 4089754, 4036902, 4036900, 3590909, 3591788, 3595090, 3800653, 3800775, 4024853, 4025184

Application

2004-2011 Freightliner, Kenworth, Cummins ISX1 / ISX Signature 450, 15.0L

Service & Support

1-Year Unlimited-Mileage Warranty
US Stock, Fast Dispatch
Bulk Orders Welcome
White-Label Support
Fully Certified

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FAQ

The HX55 (4089754 / 4036892) fits the Cummins ISX1 and ISX Signature 450, a 15.0L engine used in Freightliner, Kenworth T660/T800/W900, and other Class 8 trucks from 2004-2011. This is the non-EGR version.

No. Cummins used the HX55 model name on two different engines. The HX55 3536995 is for the M11/ISM 10.8L. This HX55 (4089754) is for the ISX 15.0L. They have different compressor and turbine sizing. Always match by part number.

No. This is a fixed-geometry turbo with no wastegate, no VGT, and no electronic components. Bolt on and go — no calibration needed.

The HX55 (this page) is oil-cooled and fits the ISX Signature 450 (450 HP). The HX55W (4046127) has a water-cooled bearing housing and fits the ISX Signature 600 (600 HP). Different turbos for different power ratings.

Brand new, 100% new components, dynamically balanced. Ships with gaskets. No core charge. One-year unlimited-mileage warranty.

Yes. US stock, volume pricing for shops, fleets, rebuilders, and distributors.

HX55 for Cummins ISX Signature 450: Fixed-Geometry Turbo for the 15L ISX

The ISX Signature 450 was one of the most popular Class 8 engines before VGT turbos took over. It ran a simple, reliable HX55 turbo with no electronic controls. When this turbo fails, it is a straightforward swap — but make sure you are ordering the right HX55, because Cummins used the same model name on two completely different engines.

HX55 for ISX (15.0L) vs HX55 for M11/ISM (10.8L)

Both are called HX55, but they are physically different turbos sized for different displacement engines:

Detail	ISX HX55 (this page)	M11/ISM HX55
Engine	ISX1 / ISX Signature 450, 15.0L	M11, ISM, ISME, 10.8L
Key part #	4089754 / 4036892	3536995 / 3590044
HP rating	450 HP	370-500 HP
Turbine housing	Twin-scroll, larger flow	Different scroll geometry

Always match by part number, not just turbo model name. The part number is stamped on the turbo nameplate.

HX55 (450 HP) vs HX55W (600 HP) on the ISX

Cummins also used the HX55W on the ISX Signature 600 — the higher-HP version. The W stands for water-cooled bearing housing. The 450 HP HX55 on this page is oil-cooled only. If your truck runs the Signature 600, you need the HX55W (4046127), not this unit.

Common failure patterns

Bearing wear — journal bearings wear after 400k-600k miles. Shaft play, oil past seals, rising EGT.
Compressor erosion — dust and debris over hundreds of thousands of miles. Power drops gradually.
Turbine housing cracks — thermal cycling on the twin-scroll housing. Exhaust soot at flanges, reduced boost.
Oil seal failure — restricted drain tube or high crankcase pressure. Blue smoke, oil consumption.