Komatsubulldozersmall ( - d39)

Komatsu DBM031_2D(S/N 41001-UP (D31S/Q-20))

Maintenance schedule, common problems & OEM parts breakdown

Search live DBM031_2D(S/N 41001-UP (D31S/Q-20)) parts

The Komatsu DBM031_2D covers the D31S-20 and D31Q-20, S/N 41001-up — the dozer-shovel (crawler loader) version of the D31 chassis, built with a front loader bucket of roughly 0.8 m3 (1.1 yd3) heaped capacity instead of a dozing blade. Two engines were fitted across this serial run: a naturally aspirated Komatsu 6D95L-1 inline-six (4.89 L) on early units S/N 41001-41183, and a turbocharged Komatsu S4D102-1 inline-four (3.92 L) from S/N 41184-up, both mechanical fuel-injection engines in the 52 kW (70 hp) class with no electronic engine controller. Operating weight runs roughly 6,780-7,120 kg (14,950-15,700 lb), varying by S versus Q trim and undercarriage/cab configuration. This -20 series dates to the early-to-mid 1990s and follows the earlier D31S-18/D31Q-18 dozer-shovel, itself part of a long-running D31 shovel-dozer lineage back through the -15/-16/-17 series. Drivetrain is torque-converter-driven with a powershift transmission, single-lever joystick steering, and steering clutch and brake final drives.

The main change inside this -20 run is the mid-production engine swap at S/N 41184, which moved from the six-cylinder naturally aspirated engine to a smaller turbocharged four-cylinder and brought a matching alternator change (13A versus 25A depending on build); the chassis, transmission, and loader geometry carried over unchanged. Komatsu did not continue the dedicated dozer-shovel body style past this generation in a documented D31-21 loader variant — the D31 dozer chassis went on as D31EX-21/D31PX-21 without the front shovel, and the compact crawler-loader niche this machine filled has largely been taken over by small wheel loaders. Surviving DBM031_2D units still turn up in landscaping, small-site earthmoving, and agricultural yard work, and the parts market for them centers on undercarriage wear components, mechanical fuel-injection parts, and torque-converter/transmission rebuild items rather than electronics.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.

Komatsu DBM031_2D(S/N 41001-UP (D31S/Q-20)) specifications

Identity & Configuration

Model range	Komatsu D31S-20 / D31Q-20 dozer shovel (crawler loader), internal factory code DBM031_2D, S/N 41001-UP
Machine type	Track-type dozer shovel fitted with a front loading bucket in place of a dozer blade; classified by spec aggregators as a crawler loader
Configurations covered	D31S-20 (standard-gauge undercarriage) and D31Q-20 (wide-gauge undercarriage) share the same engine and bucket; D31Q-20 runs a wider track gauge and shoe, giving lower ground pressure and higher weight
Contamination note	Do not merge with D31P-20/D31P-20A, D31E-20, D31PL-20, or D31PLL-20 — those are separate blade-equipped dozer models built on a related but distinct D31-20 platform with their own engine tune and specs

Engine

Engine models	Two engines across this serial run: naturally aspirated Komatsu 6D95L-1 inline-six (4.89 L) for S/N 41001-41183; turbocharged Komatsu S4D102-1 inline-four (3.92 L) for S/N 41184-up
Net power (S4D102-1, S/N 41184-up)	52 kW (69.8 hp) at 2,350 rpm
Net power (6D95L-1, S/N 41001-41183)	Not documented in the sources checked for this exact serial range — verify with your dealer
Displacement	4.89 L (298 cu in) on the 6D95L-1; 3.92 L (239.3 cu in) on the S4D102-1
Emissions tier	Pre-emissions-regulated era design (no published Tier rating in available sources); mechanical fuel system on both engines

Weights (by configuration)

D31S-20 operating weight	approx. 6,780 kg (14,947 lb)
D31Q-20 operating weight	approx. 7,120 kg (15,697 lb)
D31S-20 static tipping load	approx. 4,260 kg (9,392 lb)
D31Q-20 static tipping load	approx. 4,430 kg (9,767 lb)

Dimensions

Overall length, bucket on ground (D31S-20)	approx. 4.11 m (13.5 ft)
Overall length, bucket on ground (D31Q-20)	approx. 3.99 m (13.1 ft)
Width over tracks (D31S-20)	approx. 1.80 m (5.9 ft)
Width over tracks (D31Q-20)	approx. 2.25-2.26 m (7.39-7.4 ft)
Height to top of cab	approx. 2.65-2.71 m (8.7-8.9 ft), varies slightly by source
Dump clearance, full height	D31S-20 approx. 2.54-2.65 m (8.3-8.7 ft); D31Q-20 approx. 2.64-2.65 m (8.67-8.7 ft)
Reach at dump height	D31S-20 approx. 0.81-0.82 m (2.66-2.7 ft); D31Q-20 approx. 0.75 m (2.47 ft)
Track gauge	D31S-20 approx. 1,450 mm (57.1 in) standard gauge; D31Q-20 approx. 1,650-1,651 mm (65.0 in) wide gauge
Track shoe width	D31S-20 approx. 330 mm (13 in); D31Q-20 approx. 600-602 mm (23.6-23.7 in)
Track length on ground	approx. 1.88 m (6.17 ft), both configurations
Track rollers per side	5 (both configurations)

Performance

Maximum travel speed	approx. 6.6 km/h (4.1 mph), single speed figure published; multi-gear F/R breakdown not published in available sources
Ground pressure, D31S-20 (narrow gauge)	approx. 53 kPa (7.68-7.7 psi)
Ground pressure, D31Q-20 (wide gauge)	approx. 30-31 kPa (4.41-4.5 psi)
Breakout force, standard bucket, D31S-20	approx. 62.7-64.5 kN (14,100 lb)
Breakout force, standard bucket, D31Q-20	approx. 66.7-66.8 kN (15,000 lb)
Drawbar pull / gradeability	Not documented in the sources checked for this exact serial range — verify with your dealer or the factory shop manual

Bucket (dozer-shovel front attachment)

Bucket type	Front-mounted loader bucket; this configuration does not carry a conventional dozer blade, so no S/SU/A/VPAT blade capacities apply
Bucket capacity, heaped	approx. 0.84 m3 (1.1 cu yd), both configurations

Service Capacities

Fuel tank	approx. 115 L (30.4 gal), both configurations
Engine oil, cooling system, hydraulic tank	Not documented with reliable figures for this exact engine/chassis pairing in the sources checked — capacities published for the earlier D31S-16 (different 4D105-5 engine) do not carry over; verify with the factory shop manual or a dealer using the machine's serial number

Values vary by configuration, region, and serial range — confirm against your machine before planning transport or lifts.

DBM031_2D(S/N 41001-UP (D31S/Q-20)) fluids & capacities

System	Capacity	Recommended fluid
Engine identity note	N/A	The S/N 41001-UP range for D31S-20/D31Q-20 covers two distinct engines: S/N 41001-41183 uses the naturally aspirated 6D95L-1 (4-cycle, water-cooled, in-line 6-cylinder, 4.89 L displacement); S/N 41184-up switches to the turbocharged S4D102-1 (4-cycle, water-cooled, in-line 4-cylinder, 3.92 L displacement). Fluid capacities below are the best publicly cross-referenced figures for this D31-20 chassis family and are not separately broken out by engine sub-range — confirm against the OMM for your exact serial.
Engine crankcase (with filter)	Approx. 14.0 L (3.7 US gal)	Komatsu genuine engine oil (EO), diesel engine oil class API CD/CF. SAE 15W-40 covers most ambient ranges; Komatsu OMMs of this era also list 10W and 10W-30 grades for colder climates — follow the viscosity-by-temperature chart in the OMM for the exact cutoffs.
Cooling system	Approx. 22.3 L (5.9 US gal)	Komatsu genuine antifreeze coolant, ethylene-glycol type. Mix with water per climate, typically 30-50% concentration, richer in freezing conditions.
Fuel tank	115 L (30.4 US gal)	ASTM D975 No. 2-D diesel fuel; switch to No. 1-D or a winter blend in cold climates to prevent fuel waxing.
Powershift transmission (damper/transmission case)	Not documented in publicly available sources for this exact serial range — verify with the OMM or a Komatsu dealer.	Komatsu genuine transmission/gear oil (TO). Period Komatsu guidance for this dozer class calls for straight SAE 30 in moderate-to-warm climates and SAE 10W in cold climates.
Bevel gear / steering compartment	Not documented in publicly available sources for this exact serial range — verify with the OMM.	Same Komatsu TO gear-oil spec as the transmission case: SAE 30 in warm climates, SAE 10W in cold climates.
Final drives (each side)	Aggregator specs for this chassis family show roughly 9.8 L (2.6 US gal); not clear whether that is a per-side or combined total — confirm the split against the OMM.	Komatsu genuine TO gear oil, same SAE 30 (warm) / SAE 10W (cold) climate split as the transmission and bevel gear compartments.
Hydraulic system/tank	Not documented in publicly available sources for this exact serial range — verify with the OMM or dealer.	Small Komatsu dozers of this era commonly run engine-oil-grade fluid in the hydraulic circuit rather than a dedicated hydraulic oil. SAE 10W-30 (temperate) or SAE 15W-40 (warm) are the grades typically cited for this engine/chassis family.
Pivot shaft / equalizer bar	No oil-fill volume — grease-lubricated center pin, not an oil reservoir.	Komatsu genuine multipurpose grease at the equalizer-bar center pin per the OMM service interval.
Grease (chassis/track points)	N/A — applied by grease gun at fittings, not a fill volume.	Komatsu genuine multipurpose grease, NLGI No. 2 lithium-based for normal temperatures; NLGI No. 1 or No. 0 in cold climates for easier gun feed.

Capacities are refill values from factory literature — always fill to the dipstick/sight gauge, not the number.

Komatsu DBM031_2D(S/N 41001-UP (D31S/Q-20)) maintenance schedule

Service interval	Tasks
Every 10 h	Check engine oil level and coolant level before start-up; top off as needed Drain water and sediment from the fuel tank sump and confirm fuel level Walk the tracks: check tension, shoe and link wear, and loose bucket/lift-arm bolts Grease bucket pivot pins, lift-arm bushings, and steering clutch linkage points (weekly) Check loader/bucket hydraulic tank fluid level and look for leaks at cylinder rod seals Watch exhaust smoke color and listen for turbo whine or knock — the only failure warning on this mechanical-injection engine
Every 250 h	Change engine oil and filter (6D95L-1 naturally aspirated or S4D102-1 turbo, per serial range) Replace the fuel filter element and bleed air from the mechanical injection system Check and adjust track tension; inspect idler and roller seals for oil weep Check torque converter/transmission case oil level Service the primary air cleaner element; check turbocharger mounting bolts on S4D102-1 units Grease all bucket, lift-arm, steering clutch, and brake linkage points
Every 500 h	Change torque converter/transmission case oil and clean the suction screen Change final drive case oil on both sides Replace the loader hydraulic tank return-line filter Inspect and adjust steering clutch and brake linkage travel Check alternator charging output (13A or 25A unit depending on serial/engine) and battery electrolyte Check track shoe bolt torque and sprocket tooth wear
Every 1,000 h	Change loader/bucket hydraulic tank oil Replace fuel filter and inspect the mechanical injection pump governor linkage for wear or slop Check and adjust engine valve clearance (no electronic diagnostics on this engine — clearance drives smooth idle and starting) Check torque converter charge pump pressure Inspect track link and bushing wear; rotate or turn track shoes if uneven wear is present Replace corrosion resistor / coolant conditioner element
Every 2,000 h	Change engine coolant and flush the cooling system Pull steering clutch and brake covers for a wear inspection; reline or replace as needed Check turbocharger shaft end-play on S4D102-1-equipped units, or valve train wear on 6D95L-1 units Inspect torque converter and transmission clutch pack condition via case oil inspection and pressure check Replace the secondary air cleaner element Measure idler and roller wear against factory limits and plan undercarriage replacement
Every 4,000 h	Run a compression check and have the mechanical injection pump and injectors calibrated or pop-tested off the machine Tear down and inspect the torque converter and powershift transmission clutch packs Evaluate full undercarriage replacement — rollers, idlers, sprockets, and track chain Inspect the bucket and lift-arm structure for cracking at the pivot bosses and cutting edge, given the higher digging loads this shovel-dozer sees versus a blade dozer

Servicing the DBM031_2D(S/N 41001-UP (D31S/Q-20)) beyond the schedule

Predictive Maintenance & Fluid Analysis

No ECM on this machine, so oil and fuel condition are the early-warning system. Sample engine oil separately for 6D95L-1 (NA) versus S4D102-1 (turbo) units — turbo oil cokes faster and shows carbon loading sooner. Pull torque converter/transmission case oil for clutch material and metal fines, and final drive oil for gear wear debris. Check loader hydraulic oil for cylinder seal wear particles, and watch the fuel filter bowl for water and sediment from the mechanical injection system.

Corrective & Common Repairs

Recurring issues on this shovel-dozer: mechanical injection pump and injector wear causing hard starting, rough idle, or excess smoke, diagnosed by smoke color and compression since there is no code reader. Steering clutch and brake linkage wear shows up as steering drift or uneven turning. Loader duty cycling wears bucket pivot pins and lift-arm bushings faster than blade work would. Final drive seals weep with age, and S4D102-1 turbo bearings suffer if the engine is shut down hot without an idle-down period.

Overhaul & Rebuild Points

Undercarriage — rollers, idlers, sprockets, and track links — typically reaches rebuild limits well before the powertrain on units doing loader-style digging. Torque converter and powershift transmission clutch packs are the next major wear item, followed by steering clutch and brake relining. Engine overhaul work centers on injection pump recalibration and valve train wear rather than turbo actuator or sensor faults. Inspect the bucket and lift-arm pivot bosses for cracking — this shovel configuration sees higher digging loads than a standard dozing blade.

Seasonal & Environment Servicing

Cold starts on the mechanical injection system need a full fuel bleed and a coolant check against the antifreeze rating in use; there is no glow-plug diagnostic to lean on. Hot, dusty sites call for shorter air cleaner and radiator core cleaning intervals on both engine variants. Wet or muddy ground means more frequent track tension checks and a closer eye on steering clutch housing seals for water intrusion. For storage, treat fuel to protect the mechanical injection pump from corrosion during idle periods.

DBM031_2D(S/N 41001-UP (D31S/Q-20)) fault codes & troubleshooting

Code	Meaning	Likely cause	What to do
Charge lamp (battery/alternator symbol)	Charging circuit fault — alternator not charging the battery	Broken or slipping fan/alternator belt, faulty alternator, loose or corroded wiring	Check belt tension and condition, inspect alternator wiring and connections, test charging output
Engine oil pressure lamp	Engine lubrication pressure has dropped below the safe minimum	Low engine oil level, clogged oil filter, worn or failing oil pump	Stop the engine immediately, check oil level, inspect oil filter and pump before restarting
Coolant temperature lamp (overheat)	Engine coolant temperature has exceeded the normal operating range	Low coolant level, clogged radiator fins, loose or broken fan belt, faulty thermostat	Idle the engine, allow it to cool, check coolant level and clean radiator fins before resuming work
Air cleaner restriction indicator	Air filter element is clogged, restricting intake airflow to the engine	Dirty or clogged air filter element from dusty jobsite conditions	Inspect the air filter element and clean or replace it
Hydraulic oil temperature lamp (where fitted)	Hydraulic system oil temperature above normal range	Low hydraulic fluid level, clogged oil cooler, sustained high-load operation	Check hydraulic fluid level and cooler fins, let the system cool before continued operation

Codes and remedies are general guidance for this model family — always confirm with diagnostic tooling and your dealer before major repairs.

DBM031_2D(S/N 41001-UP (D31S/Q-20)) attachments & work tools

Blades

This serial range factory-builds as the D31S/D31Q shovel-dozer version, fitted with a front loader-type shovel/bucket (heaped capacity around 0.8 m3 / 1.1 cu yd, breakout force in the 15,000 lb-force / ~67 kN class) rather than a conventional dozing blade. Straight (S), semi-U (SU), angling (A), and hydraulic power-angle-tilt (PAT/VPAT) blades belong to the sibling D31P-20 and D31A/E-20 blade-dozer versions of the same base chassis, not to this bucket-equipped S/Q build; confirm with a dealer before assuming blade compatibility.

Rippers

Class-matched multi-shank parallelogram rippers for this dozer size (commonly 3-shank, twin-cylinder) run roughly 700-750 kg; single-shank rippers are also offered in this size class. Ripper mounting brackets are normally specified alongside a rear blade-dozer build, so whether a shovel/bucket-equipped S/Q unit in this serial range carries rear ripper linkage depends on how the individual machine was ordered — varies by configuration.

Winches

The D31 dozer family, spanning the -18 through -20/-21/-21A generations and the related KomSat I/II chassis, uses the Allied W3C PTO-driven cable winch as its class-matched unit. Exact line-pull rating for the W3C on this specific serial range is not published in general spec sheets — verify current rating with the winch manufacturer or dealer.

Drawbars/counterweights

A rear drawbar/pintle on a C-frame trunnion mount is standard on this class for towing and doubles as the winch mounting point. A bolt-on rear counterweight is typically specified only when a rear ripper or PTO winch is fitted, to balance the front bucket weight; whether one is present on a given unit varies by configuration.

Cab/ROPS guarding

Base machine ships with an operator canopy rated to ROPS/FOPS. Forestry and waste-handling builds commonly add bolt-on mesh/screen guarding over the windshield, side glass, and canopy top plus underbody guarding, but this is supplied as an aftermarket or dealer-fit kit rather than a documented factory forestry package for this exact serial range.

Hydraulic arrangement

On the S/Q shovel-dozer build, the front hydraulic circuit runs the bucket lift-and-tilt cylinders through a two-lever control, in place of the blade lift/angle/tilt circuit used on the P/A-suffix blade-dozer versions of the same chassis. A rear-mounted PTO winch draws off a separate transmission-case PTO drive, independent of the front work-equipment hydraulic circuit.

All DBM031_2D(S/N 41001-UP (D31S/Q-20)) assemblies by section

Every catalogued assembly group for the Komatsu DBM031_2D(S/N 41001-UP (D31S/Q-20)). Open an assembly to preview the parts inside — full OEM part numbers are available in Heavy Parts AI.

Hydraulic System

Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Hydraulic System : Hydraulic Piping (Tank To Pump To Valve) (For 3-Point Hitch Or Ripper) (For Multi Purpose Bucket)(#41001-41183)

01***40	Bolt,(With Air Conditioner)	4
01***20	Bolt,(For Quick Shift) (Mitsubishi)	1
01***25	Bolt,(For Canvas Canopy?Head Guard)	4
01***35	Bolt,(For Quick Shift) (Mitsubishi)	4

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Operator'S Compartment And Control System

Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Operator'S Compartment And Control System : Work Equipment Control Lever (1/2) (For Multi Purpose Bucket)

01***16	Bolt - Seat And Tether Belt Mounting	4
01***25	Bolt,(Rear Attachment Less)	1
01***30	Bolt - M8 X 30lg	3
01***25	Bolt	2

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Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Operator'S Compartment And Control System : Work Equipment Control Lever (2/2) (For Multi Purpose Bucket)

01***25	Bolt,(Rear Attachment Less)	6
01***05	Nut,L.H. (For Trimming Dozer)	1
01***06	Nut,(With Back-Up Alarm) (Op), Nut; Was 01580-10806	1
01***25	Washer,Spring?For Additional Rear Lam	6

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Service Kit And Component Parts

Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Service Kit And Component Parts : Multi Purpose Bucket Cylinder

01***26	Nut,Nylon	1
07***85	O-Ring,(For Snow Removing)	1
07***85	Ring,Back-Up? Head	1
07***34	O-Ring,(For Without Brake Assistor)	2

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Work Equipment

Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Work Equipment : Hydraulic Piping (Multi Purpose Bucket Cylinder Line) (1/2)

01***20	Bolt,(With Auto Emergency Steering)	5
01***25	Bolt,Without Revolution Sensor	4
01***20	Bolt,(For Quick Shift) (Mitsubishi)	2
01***30	Bolt,(For Quick Shift) (Mitsubishi)	1

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Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Work Equipment : Hydraulic Piping (Multi Purpose Bucket Cylinder Line) (2/2)

01***45	Bolt,(For Power Tilt Mech Angle)	8
01***40	Bolt,R.H. Outside And L.H. Inside, Bolt	2
01***30	Washer, Spring (Supplied W/Spider Assembly), Washer-Spring	8
01***42	Washer,Spring (For Pedal Steering), Washer-Spring	2

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Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Work Equipment : Multi Purpose Bucket

01***25	Bolt,(For Canvas Canopy?Head Guard)	6
01***35	Bolt,(For Quick Shift) (Mitsubishi)	4
01***95	Bolt,(For 2nd Travel Speed) (Op)	2
01***15	Screw	2

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Komatsu : Dbm031_2d(S/N 41001-Up (D31s/Q-20)) : Work Equipment : Rear Counter Weight (600kg) (For Multi Purpose Bucket)

01***16	Nut - M20	8
01***60	Flat Washer - M20 (Hardened)	8
11***10	Plate	1
11***20	Weight,Counter	3

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DBM031_2D(S/N 41001-UP (D31S/Q-20)) serial number reference

On this D31-20 generation crawler loader the PIN/serial plate is riveted to the right-hand side of the main frame, near the front, readable standing in the direction of travel. The number is also stamped into the frame itself as a backup. The serial is a plain numeric sequence following the model code (for example D31S-20 41001), with no alpha PIN prefix, since this pre-dates Komatsu's later alpha-prefix PIN convention.

Prefix	Identifies	Notes
41001	D31S-20 / D31Q-20 crawler loader, early production (S/N 41001-41183)	Covers S/N 41001-41183, the early run of the D31S-20/D31Q-20 crawler loader in the D31-20 generation. Engine is the naturally aspirated Komatsu 6D95L-1 six-cylinder diesel. Steering is mechanical, by clutch-and-brake, not hydrostatic. No alpha PIN prefix on this vintage machine; serial is a plain sequential number stamped after the model code.
41184	D31S-20 / D31Q-20 crawler loader, engine changeover (S/N 41184-up)	S/N 41184 and up, same D31S-20/D31Q-20 model line. Marks the production changeover to the Komatsu S4D102-1 engine, a turbocharged four-cylinder unit, replacing the earlier naturally aspirated 6D95L-1 six-cylinder. Parts documentation for this break also shows a higher-output alternator fitted from this point on. Steering remains mechanical clutch-and-brake. Confirm exact changeover scope with your dealer.

Frequently asked questions

What engine does the Komatsu DBM031_2D (D31S-20/D31Q-20, S/N 41001-up) use?

Two engines across this serial run: a naturally aspirated Komatsu 6D95L-1 inline-six (4.89 L) on early units S/N 41001-41183, and a turbocharged Komatsu S4D102-1 inline-four (3.92 L) from S/N 41184-up. Both are mechanical fuel-injection engines in the 52 kW (70 hp) class with no electronic engine controller or diagnostic codes.

What is the operating weight of the DBM031_2D (D31S-20/D31Q-20)?

Roughly 6,780-7,120 kg (14,950-15,700 lb), varying by configuration — D31S-20 trim runs toward the lighter end and D31Q-20 toward the heavier end depending on undercarriage and cab/canopy setup. Confirm the exact figure against the specific machine's build sheet.

What replaced the D31S-20/D31Q-20 dozer-shovel?

No confirmed direct -21 shovel-dozer successor exists. Komatsu continued the D31 dozer chassis as D31EX-21/D31PX-21 without the front loader-shovel body style, and the compact crawler-loader niche this machine filled has largely shifted to small wheel loaders in the current lineup. Verify the closest current equivalent with your dealer.

What DBM031_2D(S/N 41001-UP (D31S/Q-20)) owners discuss

What kind of machine is this really — a dozer or a loader?

It's a crawler shovel/loader built on the D31 chassis, sold under the D31S-20 and D31Q-20 designations, not a blade dozer. It carries a front-mounted loader-type shovel bucket on a lift arm and bucket cylinders instead of a dozing blade. Don't cross-shop it against blade specs or blade-related wear parts — there is no blade linkage, no tilt cylinder, and no C-frame on this machine.

What's the drivetrain and hydraulic layout like on this shovel dozer?

Power runs through a torque-converter powershift transmission into multiple-disc wet steering clutches per side, backed by external mechanical band brakes — this is standard D31-family layout, not a hydrostatic drive. The shovel's lift arm and bucket cylinders are fed off the machine's own work-equipment hydraulic pump circuit, separate from the transmission and steering-clutch oil systems. Because there are three distinct oil systems (torque converter/transmission, LH/RH steering-clutch sumps, and bevel-gear final drives) with their own dipsticks, owners commonly check the wrong dipstick and misread levels — confirm which stick you're pulling before topping off.

What engine problems show up, and does it matter which serial number you have?

Yes — this line spans two different engines by serial range, and mixing up which one you have leads to wrong parts and wrong troubleshooting. Early-range machines run a naturally aspirated inline-6 that owners on this chassis describe as smooth-running and low-stressed for the power class. Later-range machines switch to a smaller turbocharged inline-4, which is more power-dense per liter but more sensitive to air-filter condition, fuel quality, and oil change intervals — a plugged air filter or contaminated fuel shows up faster as black smoke, sluggish response, or reduced boost on the turbo engine than it did on the earlier six-cylinder. Published spec sheets for this line often list only one generic engine rating without noting the serial split, so go by your machine's own serial plate rather than a spec sheet to know which engine you actually have.

What undercarriage wear pattern is typical for this machine?

Same wear pattern as other D31-family crawler machines of this era: five track rollers per side, sealed and lubricated, wearing at the tread and flange faces over time as grit works past the seals. Track sag and roller play are the usual early symptoms; carrier rollers and idlers go next. Ground pressure on this shovel-loader configuration is comparable to the standard D31 undercarriage, so inspect roller seals for weeping oil (a sign the seal has failed and the roller is running dry) rather than relying on visual tread wear alone.

Are there known electrical or sensor issues to watch for?

This is a mechanically injected, largely non-electronic era machine — there's no engine control module and no complex sensor network to chase. What electrical issues do come up are basic charging-circuit and gauge-sender problems: a weak alternator/regulator, a failed water-temperature or oil-pressure sender giving a false warning-light reading, or a worn starter/glow-plug relay causing hard cold starts. Treat any warning-light complaint as a simple sender or wiring fault first before assuming an internal engine problem.

Owners report the inching/clutch pedal not disengaging the drive properly — what's going on, and is it safe to run like that?

This is a recurring complaint on D31-family machines: pressing the pedal applies the brake band but doesn't fully disengage the clutch pack, so the machine keeps creeping forward while the engine bogs down under load. It's almost always a linkage adjustment issue — the clutch and brake actuation points are on the same pedal travel and need to be set so the clutch releases before the brake grabs. Steering clutches that stick or bind from worn linkage or contaminated clutch oil cause the same symptom and uneven turning. Because this affects your ability to stop and control the machine, have your dealer or a qualified technician verify pedal linkage adjustment and clutch/brake timing before returning it to service.

What should I check when buying a used one of these?

First, read the serial number off the plate and confirm which engine era you're looking at (the split matters for parts and expected behavior — don't assume from the model tag alone). Start the engine cold and watch for excess smoke or slow boost response on turbo-engine units. Run the machine through turns in both directions to check for steering-clutch drag, binding, or brake grab, and pull each dipstick to confirm oil condition and that the clutch sumps haven't been cross-contaminated with transmission oil. Inspect the shovel lift-arm pins, bushings, and bucket cylinder rods for play and seal weep — this is loader-type wear, not blade wear, so check the bucket linkage pivots specifically. Walk the undercarriage for roller seal leaks and track sag. Given the steering-clutch and brake findings affect safe operation, have your dealer verify clutch and brake condition before you rely on the machine in the field.

Compiled from owner and technician discussions across the industry — experiences vary by serial range and machine history.

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