Case 590 Turbo Backhoe Loader: Specs, Parts & Common Issues
Produced 1990 through 1995 - the larger-frame turbocharged sibling to the 580K / 580 Super K, sharing the same JJG-prefix Phase III integrated transaxle and wet-disc brakes but with a stronger backhoe and loader. Cummins 4T-390 turbo, Carraro 26.18 4WD optional, Extendahoe commonly fitted.
The Case 590 Turbo started Case's 590-line backhoe loader in 1990 as the larger-frame, higher-output sibling to the 580K / 580 Super K. Production ran approximately 1990 through 1995, when the 590 Super L took over the larger-frame slot in the L generation. The 590 Turbo shares the same chassis VIN family (JJG prefix), the same Phase III integrated transaxle introduced on the 580K mid-production, the same wet-disc multi-plate brake architecture, and the same Carraro 26.18 4WD front axle as the 580 Super K. What's bigger on the 590 Turbo is the iron - heavier backhoe, larger loader bucket, and longer reach.
Because the 590 Turbo shares so much architecture with the 580 Super K, most service parts cross between the two. Engine internals, transaxle components, wet-disc brake parts, and front axle assemblies all interchange. The 590-specific parts are the backhoe boom, dipper stick, loader frame, and the larger hydraulic cylinders.
At-a-glance specifications
Case 590 Turbo - factory specifications
- Production years
- 1990 - 1995
- Serial prefix
- JJG (same family as 580K / 580 Super K)
- Engine
- Cummins 4T-390 (4BT 3.9L turbocharged)
- Cylinders
- 4, turbocharged direct-injection diesel
- Displacement
- 239 cu in (3.9 L)
- Bore × stroke
- 4.02 in × 4.72 in (102 × 120 mm)
- Power
- ~86 HP net / ~93 HP gross
- Torque
- 351 Nm (~259 lb-ft)
- Transmission
- Case Phase III integrated transaxle, 4-speed Powershift with power shuttle
- Brakes
- Wet-disc multi-plate, hydraulically actuated
- Front axle
- 2WD standard; Carraro 26.18 4WD optional
- Operating weight
- ~15,740 lb (7,139 kg)
- Transport length
- ~23 ft 6 in (7.16 m)
- Transport width
- ~7 ft 3 in (2.22 m)
- Transport height
- ~8 ft 8 in (2.64 m)
- Hydraulic flow
- 137 L/min (~36 gpm)
- Loader bucket capacity
- 1.2 m³ (~1.6 cu yd)
- Backhoe dig depth (standard)
- ~15 ft 9 in (4.76 m)
- Backhoe dig depth (Extendahoe)
- ~18 ft (5.5+ m)
- Backhoe bucket dig force
- ~15,430 lb (7,000 kg)
- Max travel speed
- ~25 mph (40 km/h)
Production years and serial numbers
The 590 Turbo was produced from 1990 through 1995, with the JJG prefix shared across the 580K / 580 Super K / 590 Turbo K-generation chassis family. Pilot units shipped in late 1990 (only 7 units in the 1990 model year per published serial breaks), with full production from 1991 through early 1995 before the 590 Super L replaced it.
| Year | Beginning serial | Ending serial |
|---|---|---|
| 1990 (pilot) | JJG0205001 | JJG0205007 |
| 1991 | JJG0205008 | JJG0206405 |
| 1992 | JJG0206406 | JJG0206700 |
| 1993 | JJG0206701 | JJG0207313 |
| 1994 - 1995 | JJG0207314 | - |
Engine and powertrain
The 590 Turbo is powered exclusively by the Cummins 4T-390 - the turbocharged variant of the 4B 3.9L Cummins engine family that powers most Case construction equipment of the K-generation. 239 cubic inches, four-cylinder, direct-injection diesel with a turbocharger. Approximately 86 HP net / 93 HP gross with 351 Nm of torque. The same engine and turbo assembly cross to the 580 Super K and the Case 450C dozer of the same era.
Transmission is Case's Phase III integrated transaxle - the same drivetrain introduced on the 580K mid-production and continued through the entire 580 Super K and 590 Turbo run. 4-speed Powershift with hydraulic forward/reverse shuttle. The integrated transaxle bolts directly to the back of the engine; there is no separate Borg-Warner shuttle assembly like the earlier Phase I 580K. All shifting is hydraulically actuated through the transmission control valve.
Wet-disc brakes
The 590 Turbo uses oil-bath wet-disc multi-plate service brakes, hydraulically actuated, integrated into the rear transaxle - same as the 580 Super K. Friction plates run in Hy-Tran transmission oil. Use Hy-Tran Plus (or equivalent with wet-brake friction modifier) - generic UTF or gear oil will glaze the discs.
Common problems documented by owners
Shift fork breakage in the Phase III transaxle
Documented failure mode on the 590 Turbo and 580 Super K Phase III transaxles. Symptom: transmission locks up when a fork breaks and a gear engages partially. Service requires top-cover removal to identify the broken fork.
Cummins 4T-390 fuel system priming
The 4BT/4T-390 lift pump is fiddly to bleed after a filter change. Cracking the high-pressure injector lines is often required to get fuel up to the injection pump. This is the single most-searched 590 Turbo issue on the forums.
Turbo wastegate and boost-leak issues
Power loss and lugging in higher gears - frequently traced to turbo wastegate failure or boost leaks at the intake plumbing. Replacement turbocharger (J802290) cross-fits 580K, 590 Turbo, and Case 450C.
Hydraulic pump wear
Engine stalls under hydraulic load with system pressure below ~2,800 psi spec. Main relief valve, worn pump, or PRV seat. Combined hydraulic + travel demand exposes the weakness.
Wet-disc brake drag or contamination
Common K-generation issue - brake oil shares the transaxle, so a brake-piston seal failure puts hydraulic oil into the brake packs and contaminates the friction surfaces.
Carraro 4WD front-axle kingpin wear
Documented service item on 4WD-equipped 590 Turbos. Kingpin kits and bushings cross from the 580 Super K Carraro 26.18 axle catalog.
Parts scarcity on 590-specific castings
Case built far more 580-series machines than 590s in the K generation, so 590-specific castings (boom 140505A1, dipper stick, loader frame) get harder to source over time. Used and rebuilt options are stocked.
Replacement parts
| Part | SKU | Notes |
|---|---|---|
| Cummins 4T-390 Turbocharger | J802290 | Replacement turbo for 590 Turbo, 580K Super K, and Case 450C - same Cummins 4T/4TA-390 family |
| Radiator | A189481 | Direct-fit replacement radiator for 590 Turbo |
| Steel Backhoe Boom (USA-Made) | D150756 | OEM-style replacement steel backhoe boom - addresses the 590-specific casting scarcity |
| Ring Gear & Pinion Set | A190330 | Differential ring and pinion for 590T and 580 Super K - cross-fitment |
| Filter Maintenance Kit (Phase III) | CS-580KIII-FK | Complete filter service kit for 580K Phase III and 590 Turbo |
| Cummins 4-390 Overhaul Kit | BEKC39 | Cummins 4B 3.9L engine overhaul - covers the 4T-390 long block internals |
| Cummins 4B / 4BT Long Block | CS-4390-LB-N | Replacement long-block engine |
Browse by 590 Turbo-fit category
- Wet-Disc Brakes - 580K, 580 Super K, 590 Turbo
- 580K, 580 Super K, 590T Front Axle Parts (4WD)
- 4WD Carraro Front Axle - 580K family
- Rear Axle - 580K Phase III, Super K, 590 Turbo
- Pins, Bushings & Links - 590 Turbo / Super L / Super M / Super N
- Case Backhoe Parts - full catalog
Frequently asked questions
What years was the Case 590 Turbo made?
1990 through 1995, with pilot production in late 1990 and full volume production from 1991 onward. The 590 Super L replaced the 590 Turbo in 1995.
What engine is in a 590 Turbo?
The Cummins 4T-390 (4BT 3.9L) - a 239-cubic-inch four-cylinder turbocharged diesel rated ~86 HP net / ~93 HP gross. Same engine as the 580 Super K and the Case 450C dozer.
What's the difference between the 590 Turbo and the 580 Super K?
Both use the same engine, the same Phase III integrated transaxle, the same wet-disc brakes, and the same Carraro 4WD axle. The 590 Turbo has a larger frame, heavier backhoe (with deeper Extendahoe reach), and a 1.6 cu yd loader bucket vs. the Super K's smaller bucket. Most non-backhoe parts cross between the two.
Does the 590 Turbo have wet-disc brakes?
Yes - same wet-disc multi-plate architecture as the 580K and 580 Super K. Use Hy-Tran Plus only.
Does the 590 Turbo have 4WD?
Carraro 26.18 4WD was offered as a factory option. Most North American units shipped with 4WD given the 590's heavier loader and backhoe.
Where is the serial number on a Case 590 Turbo?
Stamped on a data plate inside the cab on the left dashboard, with a secondary stamping on the chassis near the front axle. All 590 Turbo serials carry the JJG prefix.
Need parts for your Case 590 Turbo?
Cummins 4T-390 engine overhaul kits and long blocks, Phase III transaxle components, wet-disc brake parts, Carraro 26.18 4WD axle parts, USA-made replacement backhoe booms, and complete filter maintenance kits - most parts cross from the 580 Super K catalog. Talk to a tech: (800) 909-7060, Mon-Fri 7a-5p CT.
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