Model Spotlight

Case 590 Super L Backhoe Loader: Specs, Parts & Common Issues

Produced 1995 - 2001, the 590 Super L is the larger-frame L-generation Construction King - same Cummins 4T-390 turbocharged engine and L-generation cab as the 580 Super L, but on a substantially larger chassis with stronger backhoe and loader iron, ~95-100 HP gross. Series I / Series II split brought a Powershift transmission option to the larger backhoe.

BT

Broken Tractor Editorial Team• Updated May 2026• 9 min read

The Case 590 Super L is the larger-frame turbocharged L-generation Construction King backhoe loader. It came to market in 1995, replacing the 590 Turbo, and ran through 2001 before the 590 Super M took over. The 590 Super L runs the same Cummins 4T-390 turbocharged 4-cylinder diesel as the 580 Super L, on the same L-generation cab platform, but with a substantially larger frame, stronger backhoe boom and dipper, larger loader bucket, and heavier counterweight. Net power is approximately 95-100 HP gross - modestly higher than the 580 Super L's 86 HP net.

For owners maintaining a 590 Super L today, most service parts cross-fit with the 580 Super L on shared systems (engine, transmission base, cab, brakes, hydraulics) and with the 590 Super M that succeeded it on shared chassis items. The Series I / Series II split mirrors what happened on the 580 Super L - different filter kits, different hydraulic tank, and the optional Powershift transmission introduced on Series II.

At-a-glance specifications

How the 590 Super L differs from the 580 Super L

The 590 Super L and 580 Super L share the same engine, transmission base architecture, cab, brakes, hydraulics, and many service items. The 590 differences are physical-iron - it's a larger, heavier machine designed for tougher digs and bigger loads:

• Larger chassis - heavier frame, stronger axle, increased operating weight (~16,500-18,500 lb vs. 580 Super L's ~14,500-17,000 lb).
• Bigger backhoe iron - stronger backhoe boom, longer dipper stick options, larger swing tower. The 294300A1-U inner dipper is 590-specific (cross-fits 590 Super M).
• Larger loader bucket and frame - heavier loader frame, larger bucket capacity; the 133936A1 loader lift cylinder is 590-specific.
• Power output - 590 Super L approximately 95 HP net vs. 580 Super L's 86 HP net. Both run the same engine block, with slight calibration differences for the heavier machine.
• Hydraulic pump - the 257955A1 590-specific pump cross-fits 590 Super M. The 580 Super L uses a different pump (87433897 cross-fits 580SL/SM).
• Cylinders - most hydraulic cylinders are 590-specific (larger bore or longer stroke). The 175785A1 boom cylinder, 140965A1 dipper cylinder, and 296434A1 bucket cylinder are all 590 Super L / Super M cross-fits.

How the 590 Super L differs from the 590 Turbo

The 590 Super L is the L-generation successor to the 590 Turbo (the K-generation larger-frame turbocharged backhoe). The defining changes:

• Cab and operator station - completely redesigned L-generation cab with better visibility, refined controls, improved HVAC.
• 17-spline hydraulic pump shaft - the 590 Super L uses the L-generation 17-spline pump shaft. The 590 Turbo used a different spline configuration. Pumps do NOT interchange between K and L generations.
• Same Cummins 4T-390 engine - the engine carries forward unchanged with calibration refinements. Engine internals interchange between the 590 Turbo and 590 Super L.
• Same wet-disc brakes - wet-disc multi-plate brakes carry forward.

Engine and powertrain

Same engine as the 580 Super L. Cummins 4BT 3.9L turbocharged 4-cylinder, Bosch in-line injection pump, wastegated turbocharger. The Cummins B-series industrial-engine ecosystem provides broad service-parts availability - pistons, rings, bearings, head gasket sets, water pumps, oil pumps, and many valve train items source through both Case-branded and Cummins B-series channels.

The wastegated turbocharger is the most common engine-service item. Replace at the first sign of bearing wear - symptoms include blue smoke at startup or under throttle, oil consumption, audible whine, or visible compressor wheel shaft play.

Powershift transmission (Series II option)

The 590 Super L Series II introduced an optional Powershift transmission, the same as on the 580 Super L Series II. The 336551A1 Powershift controller is the standard service item when the Powershift goes into limp mode or refuses to shift cleanly. Cross-fits 580 Super L Series II and 590 Super L Series II.

Routine service parts for the 590 Super L

The table below covers routine service and high-cross-fit parts for the 590 Super L. Many parts also cross-fit with the 580 Super L and the 590 Super M, broadening the practical parts pool.

For additional 590 Super L cross-fit parts, see: 296434A1 bucket cylinder, 175785A1 boom cylinder, 140965A1 dipper cylinder, and 133936A1 loader lift cylinder - all 590 Super L / 590 Super M cross-fits. For a comprehensive search, browse the Case backhoe loader parts hub.

Common issues and what to expect

Turbocharger wear

The 4T-390 wastegated turbocharger is the most common engine-service item. Same engine as the 580 Super L - same wear pattern. Symptoms: blue smoke, oil consumption, audible whine, shaft play. Replace at first sign of bearing wear.

Series I vs Series II parts ordering

Filter kits and Powershift parts differ between Series. Always confirm serial number before ordering Series-specific parts. The CS-590SLIIT-FK-1 Series II filter kit will not fit a Series I machine.

Hydraulic cylinder seal failure

Every cylinder on a 25-plus-year-old 590 Super L has seals well past expected service life. The CS-SK-5 590 Super L cylinder seal kit package covers the major cylinder rebuild components in one bundle.

Hydraulic pump wear

The 257955A1 17-spline hydraulic pump wears over time. Symptoms: lazy boom and dipper, weak stabilizers, longer cycle times under load.

Cooling system service

The 233817A1 hydraulic oil cooler is a common cooling-system replacement item across 580L/SL/590SL. The original radiator and cooler internals corrode over 25-plus years.

Brake service

The 243894A1 brake kit covers the wet-disc brake rebuild - 4 × 237017A1 disc and 2 × 237018A1 plate. Use when wet-disc brakes lose holding pressure after sustained service.

Powershift transmission service (Series II option)

If your 590 Super L Series II has the Powershift, the 336551A1 controller is the standard service item when shifting becomes erratic.

Cab glass and seal aging

The D126198 rear cab glass seal bar and 108513A1 front knee glass rubber channel are routine cab service items as the original rubber dries out and cracks.

Where the 590 Super L sits in the Construction King family

The 590 Super L is the larger-frame turbocharged L-generation Case backhoe loader. It runs alongside the 580 Super L (same engine, smaller chassis) and replaces the K-generation 590 Turbo. After the 590 Super L came the 590 Super M (2001-2008), which replaced the Cummins 4T-390 with the Case 445T/M family and continued the L-generation cab and hydraulics forward.