Machine models
Cat 797B: shift controls, oil renewal and altitude equipment
Coasting and shift complaints on the 797B
The B-Series control system deliberately refuses some driver requests. Its neutral-coast inhibitor keeps the transmission engaged above the published coasting threshold to protect lubrication. The body-up reverse neutralizer has a different trigger: activating the hoist while reverse is selected sends the transmission to neutral.
A truck that changes gear selection during a dump cycle therefore needs its hoist command and body position recorded with the event.
Anti-hunt logic also delays another shift immediately after a gear change when the truck is operating near a shift point. That delay is not, by itself, evidence of a slipping clutch. The service record should separate a commanded shift that the control prevented from a shift that occurred but failed to transmit torque.
Caterpillar’s Electronic Technician can retrieve the stored engine and transmission information needed for that distinction.
The traction-control system acts on rear-wheel speed differences through the oil-cooled brakes. Retarding is distributed across the wheels, but traction correction and the automatic retarder have different jobs. Record which system was active before attributing every brake application to the same cause.
Source: Caterpillar AEHQ5511, December 2003, control integration and braking sections.Oil-renewal equipment changes what an oil-use record means
The optional Oil Renewal System draws oil from the engine sump for combustion and requires replacement oil to be supplied continually. Consumption recorded on an equipped truck therefore includes intentional renewal. Ask whether that system was installed and operating before comparing its make-up-oil record with an unequipped 797B.
The brochure’s extended service-interval claim belongs to the optional system, not to every truck carrying the model name.
Altitude equipment is another choice. Cat specifies a normal arrangement and a separate high-altitude package, with different derating boundaries. A high-elevation power complaint needs the engine arrangement identified before the normal low-altitude curve is used.
The common 3524B name alone cannot establish which calibration and air system are fitted.
Source: 797B engine and serviceability specifications.| Model and field | Earlier entry | Manufacturer figure and scope | Source |
|---|---|---|---|
| 797B Diff And Final Drive Fluid Capacity | 110 gal | 185 US gal (701 L), differentials and final drives; AEHQ5511 December 2003 | Original document |
| 797B Rated Payload | 793,664 lb | 760,000 lb calculated from 380 US tons; brochure rounded metric nominal 345 tonnes; AEHQ5511 December 2003 | Original document |
| 797B Alternator Supplied Amperage | 75 amps | 75 A each; two alternators, 24 V system; AEHQ5511 December 2003 | Original document |
| 797B Hydraulic System Fluid Capacity | 263 gal | 263 US gal (996 L), brake/hoist TANK ONLY; complete brake/hoist system 486 US gal (1842 L) | Original document |
| Listing-entry count |
|---|
| 1 |
Cat 797B: shift controls, oil renewal and altitude equipment: rigid rock truck.
| Configuration | Documented field and quantity |
|---|---|
| 797B |
|
| Specification | 797B |
|---|---|
| Overall Length | 47.67 ft |
| Overall Width | 30.03 ft |
| Overall Height | 24.88 ft |
| Wheelbase | 23.62 ft |
| Ground Clearance | 2.85 ft |
| Dump Height | 50.17 ft |
| Dump Ground Clearance | 6.17 ft |
| Specification | 797B |
|---|---|
| Dump Angle | 45 degrees |
| Lower Time | 18.5 sec |
| Load Capacity - Heaped | 287.75 yd3 |
| Rated Payload | 760,000 lb calculated from 380 US tons; brochure rounded metric nominal 345 tonnes; AEHQ5511 December 2003 |
| Raise Time | 25 sec |
| Specification | 797B |
|---|---|
| Number Of Cylinders | 24 |
| Engine Model | 3524B HD EUI |
| Gross Power | 3,550 hp |
| Net Power | 3,370 hp |
| Power Measured @ | 1,750 rpm |
| Aspiration | Turbocharged |
| Displacement | 7,143 cu in |
| Specification | 797B |
|---|---|
| Fuel Capacity | 1,800 gal |
| Cooling System Fluid Capacity | 315 gal |
| Engine Oil Capacity | 110 gal |
| Diff And Final Drive Fluid Capacity | 185 US gal (701 L), differentials and final drives; AEHQ5511 December 2003 |
| Steering System Fluid Capacity | 114 gal |
| Brake/Hoist System Fluid Capacity | 486.7 gal |
| Brake Hoist Tank Capacity | 263 US gal (996 L), brake/hoist TANK ONLY; complete brake/hoist system 486 US gal (1842 L) |
| Operating Voltage | 24 V |
| Alternator Supplied Amperage | 75 A each; two alternators, 24 V system; AEHQ5511 December 2003 |
| Tire Size | 59/80R63 Standard Tires |
| Specification | 797B |
|---|---|
| Transmission Type | Seven-speed planetary powershift with direct-injection |
| Number Of Gears - Forward | 7 |
| Number Of Gears - Reverse | 1 |
| Max Speed | 42 mph |
| Specification | 797B |
|---|---|
| Empty Weight | 584,225 lb |
| Loaded Weight | 1,375,000 lb |
| Weight Distribution Front - Empty | 43.5 % |
| Weight Distribution Rear - Empty | 56.5 % |
| Weight Distribution Front - Loaded | 33.3 % |
| Weight Distribution Rear - Loaded | 66.7 % |
| Figure | 797B |
|---|---|
| Engine horsepower per 1,000 lb of weight | 5.8 |
| Fuel tank per engine horsepower | 0.53 gal |
| Rated payload per cubic yard of heaped body | 2,758 lb |
| Equipment group | rigid rock truck |
|---|
| Brand | Equipment group | Compared entry | Sort order |
|---|---|---|---|
| Cat | rigid rock truck | 797B | Descending quantity; 1 is largest |
| Figure | 797B | Rank | Lowest in line | Highest in line |
|---|---|---|---|---|
| Engine power | 3,370.0 hp | 3 of 24 | 450.0 hp | 4,000.0 hp |
| Listed weight | 584,225 lb | 1 of 14 | 66,500 lb | 584,225 lb |
| Fuel capacity | 1,800.0 gal | 1 (tied) of 22 | 140.0 gal | 1,800.0 gal |
| Horsepower per 1,000 lb | 5.8 hp | 13 of 14 | 5.8 hp | 10.1 hp |
| Rated payload | 793,664.0 lb | 1 of 14 | 79,000.0 lb | 793,664.0 lb |
| Base version | 797 | 797B | 797F |
|---|---|---|---|
| Engine power | 3,211 hp | 3,370 hp | 4,000 hp |
| Weight | 797: 510,000 lb; 797B: 584,225 lb | ||
| Fuel capacity | 1,800 gal | 1,800 gal | 1,000 gal (US) |
| Wheelbase | 23.63 ft | 23.62 ft | 23.58 ft |
| Rated payload | 797: 760,000 lb; 797B: 793,664 lb | ||
History and service record of 797B
- What changed from the original 797. Caterpillar introduced the 797B in spring 2002 to replace the first-generation 797, raising payload capacity by 20 short tons to 380 ST and increasing the Cat 3524B EUI 24-cylinder diesel's output from a net 3211 hp to 3370 hp, which let the 797B hold a 42 mph top speed at the heavier load, 2 mph faster than the original truck could manage loaded. Wikipedia, Caterpillar 797.
- In service. The first 797B units entered service with customers in October 2002. Wikipedia, Caterpillar 797.
- Approximate price. Caterpillar 797-series trucks have been priced at roughly $3.4-5 million each, varying with the individual customer's specification. Wikipedia, Caterpillar 797.
| Forum index | Equipment class queried | Names in the search | Matching titles |
|---|---|---|---|
| Heavy Equipment Forums | rigid rock truck | Cat and the 797B. That is too few titles to say what owners mostly ask about, so the most recent are listed instead | 1 |
- CAT 797b Scale Model (Heavy Equipment Forums, 2025-09-01)
| Date | Listing index | Equipment class | Names queried | Result |
|---|---|---|---|---|
| 2026-09-24 | MachineryTrader (machinerytrader.com) | rigid rock truck | 797B | No matching offers in this snapshot |
| Date | Database | Names queried | Result |
|---|---|---|---|
| 2026-09-24 | U.S. Consumer Product Safety Commission | Cat; 797B | No matching recall in the stated search |
| Evidence class | Document, classification and recorded date |
|---|---|
| Reference site |
|
| Forum threads |
|
| Published history |
|
| Federal agency data |
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Cat 797B: shift controls, oil renewal and altitude equipment: Configuration records
797B
| Specification | Source figure |
|---|---|
| Engine | |
| Gross Power | 3,550 hp |
| Net Power | 3,370 hp |
| Number Of Cylinders | 24 |
| Power Measured @ | 1,750 rpm |
| Aspiration | Turbocharged |
| Dimensions and weight | |
| Overall Width | 30.03 ft |
| Overall Height | 24.88 ft |
| Wheelbase | 23.62 ft |
| Dump Height | 50.17 ft |
| Dump Ground Clearance | 6.17 ft |
| Dump | |
| Rated Payload | 760,000 lb calculated from 380 US tons; brochure rounded metric nominal 345 tonnes; AEHQ5511 December 2003 [source] |
| Load Capacity - Heaped | 287.75 yd3 |
| Dump Angle | 45 degrees |
| Operational | |
| Fuel Capacity | 1,800 gal |
| Tire Size | 59/80R63 Standard Tires |
| Cooling System Fluid Capacity | 315 gal |
| Engine Oil Capacity | 110 gal |
| Diff And Final Drive Fluid Capacity | 185 US gal (701 L), differentials and final drives; AEHQ5511 December 2003 [source] |
| Steering System Fluid Capacity | 114 gal |
| Brake/Hoist System Fluid Capacity | 486.7 gal |
| Operating Voltage | 24 V |
| Alternator Supplied Amperage | 75 A each; two alternators, 24 V system; AEHQ5511 December 2003 [source] |
| Transmission and speeds | |
| Max Speed | 42 mph |
| Transmission Type | Seven-speed planetary powershift with direct-injection |
| Number Of Gears - Forward | 7 |
| Number Of Gears - Reverse | 1 |
| Weights | |
| Empty Weight | 584,225 lb |
| Loaded Weight | 1,375,000 lb |
| Weight Distribution Front - Empty | 43.5 % |
| Weight Distribution Rear - Empty | 56.5 % |
| Weight Distribution Front - Loaded | 33.3 % |
| Weight Distribution Rear - Loaded | 66.7 % |
| Additional specifications | |
| Overall Length | 47.67 ft |
| Ground Clearance | 2.85 ft |
| Lower Time | 18.5 sec |
| Raise Time | 25 sec |
| Engine Model | 3524B HD EUI |
| Displacement | 7,143 cu in |
| Brake Hoist Tank Capacity | 263 US gal (996 L), brake/hoist TANK ONLY; complete brake/hoist system 486 US gal (1842 L) [source] |
| Oil Renewal System Scope | Optional ORS intentionally consumes sump oil in combustion and needs continuous make-up oil; extended interval is equipment-dependent, not a universal service instruction. [source] |
| Altitude Arrangement Scope | AEHQ5511: standard derating starts 2591 m (8500 ft); optional HAA no derating between 3048–4572 m (10000–15000 ft). [source] |
| December 2003 Body Weight Boundary | Chassis with hoist, body mounting group and tires 214820 kg (473600 lb); body range 38000–63000 kg (84000–140000 lb); actual body and equipment determine empty weight. [source] |
More in Cat: 794 AC/796 AC/798 AC, 797: engine modules/supports/original specs, 797F: retarding arrangements/body options/controls.