BorgWarner Schwitzer S2A Turbocharger: John Deere & Case Equipment Guide

The BorgWarner Schwitzer S2A Turbocharger is one of the most widely used chargers in agricultural and construction equipment, and if you run John Deere or Case machines built from the late 1980s through the 2010s, there’s a strong chance you’ve got one bolted to your engine right now. It’s a fixed-geometry, single-stage unit engineered for the mid-displacement diesels that power tractors, backhoes, skid steers, combines, and wheel loaders. This guide breaks down what the S2A is, where it lives in the John Deere and Case lineup, how to spot a failing unit, and what it costs to fix it right the first time.

PT Turbo has been rebuilding and supplying turbochargers since 1978, more than 45 years of hands-on experience with Schwitzer, Garrett, and Mitsubishi units. We stock both new and remanufactured parts, so the recommendations below come from decades of actually turning wrenches on these machines.

What Is the BorgWarner Schwitzer S2A Turbocharger?

The S2A belongs to BorgWarner’s Schwitzer “S2” family, a small-frame journal-bearing turbo designed for engines roughly in the 3.0 to 4.5 liter displacement range. Schwitzer was a legacy turbo brand absorbed by BorgWarner, and you’ll still see both names cast into the housings and stamped on the nameplate depending on the production year.

The “S2” designates the frame size and the “A” designates the compressor and turbine wheel trim package. It’s a proven, no-nonsense design: cast iron turbine housing, aluminum compressor cover, and a floating journal bearing system fed by pressurized engine oil. There’s no electronic actuator and no variable geometry on the base S2A, which is exactly why fleet owners like it. Fewer moving parts means fewer failure points.

If you want a deeper primer on how these units work, BorgWarner publishes technical resources at borgwarner.com, and there’s a solid general overview of turbocharger operation on Wikipedia.

Typical S2A Specifications

Attribute	Typical S2A Spec
Frame size	S2 (small frame)
Engine displacement range	3.0L to 4.5L diesel
Bearing system	Journal (floating) bearing, oil lubricated
Turbine housing	Cast iron, fixed geometry
Compressor cover	Cast aluminum
Wastegate	Internal or external depending on application
Typical boost	18 to 30 psi

John Deere and Case Applications for the S2A

The S2A shows up across a broad slice of the John Deere PowerTech and Case/CNH lineup. It was a go-to charger for the 4045 (4.5L) and smaller 3029 (3.0L) John Deere engines, and for the equivalent Case IH 4-cylinder diesels found in compact and utility tractors, backhoe loaders, and skid steers.

Common platforms where you’ll find an S2A or its close variant include:

• John Deere 4045T and 4045H PowerTech engines (tractors, backhoes, combines)
• John Deere 3029T in compact utility tractors
• Case IH Maxxum and JX series utility tractors
• Case 580 series backhoe loaders
• Case skid steer loaders with 4-cylinder diesels
• New Holland equivalents sharing CNH driveline components

Because Deere and Case both sourced from Schwitzer/BorgWarner during overlapping years, cross-referencing by nameplate part number is critical. Two machines that look identical can carry different wheel trims. Always match the number stamped on the compressor housing, not just the engine model.

If your equipment runs a larger engine, the S2A’s bigger siblings cover those needs. Our Caterpillar C9 BorgWarner S200 guide and the Detroit Series 60 S300 guide walk through the S200 and S300 frames used on heavier applications.

Symptoms of a Failing BorgWarner Schwitzer S2A Turbocharger

An S2A rarely dies without warning. The trick is reading the early signs before a spun bearing sends metal through your engine. Here’s how the symptoms typically progress by severity.

Severity	Symptoms	What It Usually Means
Early	Slight loss of power, whistling or siren noise on acceleration	Compressor seal weeping, minor shaft play
Moderate	Blue/black smoke, oil in the intake pipe, sluggish throttle response	Bearing wear, seal failure, oil migration
Severe	Grinding/rattling, no boost, heavy oil consumption, metal in oil	Spun bearing, wheel contact, imminent catastrophic failure

Excessive oil consumption is the most misdiagnosed symptom. Before you condemn the turbo, check the crankcase ventilation and the return oil line for restriction. A blocked oil drain will pressurize the center housing and push oil past healthy seals every time.

Quick Field Checks Before You Pull the S2A

• Grab the compressor wheel and check for shaft play. Axial (in/out) movement should be barely perceptible; radial wobble that lets the wheel contact the housing means it’s done.
• Inspect the compressor wheel blades for chips or bent tips, a sign of debris ingestion.
• Look for oil pooling in the compressor cover or turbine housing.
• Verify the wastegate actuator moves freely and holds boost pressure.

Wastegate Actuators and Replacement Parts

On wastegated S2A applications and the related small-frame chargers used across Deere and Case equipment, the pneumatic actuator is a frequent failure point that gets blamed on the whole turbo. When the diaphragm cracks or the rod seizes, you lose boost control and throw yourself into a fault code chase. Replacing the actuator is far cheaper than replacing the cartridge.

PT Turbo stocks a range of pneumatic actuators that fit these small and mid-frame diesel turbo platforms. For Garrett-based setups on the same class of machinery, the Garrett Pneumatic Actuator 757979-5102 is available for $240.94, and the heavier-duty Garrett Pneumatic Actuator 445963-0040 runs $465.52 for higher-boost applications.

If you’re working on Mitsubishi TD03-style chargers found on smaller compact equipment and light diesels, the Mitsubishi TD03 Pneumatic Actuator 49S3118761 is $104.33, and the budget-friendly Mitsubishi Pneumatic Actuator 4918918935 is just $83.99. Matching the actuator spring pressure to your engine’s boost target matters, so verify the calibration before you install.

Not sure which actuator matches your nameplate number? Send us your part number through the PT Turbo contact page and we’ll cross-reference it.

New vs Remanufactured S2A: Cost and Value

For most Deere and Case owners, a properly remanufactured S2A is the smart buy. A quality reman uses new bearings, seals, thrust components, and a balanced core, then gets VSR (Vibration Sorting Rig) balanced to OEM spec. The performance is identical to new at a meaningful discount.

Option	Typical Price Range	Best For
New OEM S2A	$700 to $1,200	Warranty-critical machines, dealer requirements
Remanufactured S2A	$350 to $650	Best overall value, most fleet and owner-operator work
Actuator/seal repair only	$85 to $470	Boost control faults, minor oil weeping

Browse our remanufactured turbochargers or the full turbo catalog to check current stock. If you’d rather keep your original core, our turbocharger rebuild service restores your unit to spec with a full inspection, balancing, and testing.

Why Balancing Matters on the S2A

These journal-bearing chargers spin well past 100,000 rpm. A cartridge that isn’t precision balanced will chew through bearings in a season.

Cross-Reference & Superseded Part Numbers

The turbochargers covered in this article match or supersede the following OEM and manufacturer part numbers. If you are searching by part number, these are the units stocked by PT Turbo for this application:

479514-RMN  •  53047109901-BILLET  •  53047109904-BILLET  •  A4720901480-RMN  •  NEW-FTR-TWN-TRB  •  RMN-BRG-V2S-TWN  •  RMN-BRG-V2S-TWN-GR-TO  •  RMN-BRG-V2S-TWN-NO

Can’t find your number above? Contact PT Turbo — our team has been matching part numbers since 1978.