Big Bud 400/20
The Big Bud 400/20 is a tractor produced by Big Bud. It is equipped with a 736 ci 12.1 L engine. The listed engine power is Diesel (listed): 400 hp / 298.3 kW. Transmission: Fuller Roadranger RT 12513. Operating weight: 40000 lbs 18144 kg.
Engine Power
Diesel (listed): 400 hp / 298.3 kW
Fuel & Capacities
550 gal
2081.8 L
Transmission
Fuller Roadranger RT 12513
Operating Weight
40000 lbs
18144 kg
Overview
 | 1979 - 1981
3 SeriesFour-wheel Drive (4WD) tractor
3 Series
Four-wheel Drive (4WD) tractor |
|---|
Production | |
|---|---|
Manufacturer | Big Bud |
Four-wheel Drive (4WD) tractor | |
Built in Havre, Montana, USA | |
Original price was $109,000 in 1978 | |
Variants | |
|---|---|
400/20 | gear shift |
400/30 | power shift |
Big Bud 400/20 Engine | |
|---|---|
Detroit Diesel 12.1L 8-cyl diesel | |
Fuel tank | 550 gal
2081.8 L |
Engine details ...  | |
Big Bud 400/20 Transmission | |
|---|---|
12-speed gear | |
Transmission details ...  |
Big Bud 400/20 Power | |
|---|---|
Engine | 400 hp
298.3 kW |
Mechanical | |
|---|---|
Four-wheel drive | |
Final drives | planetary |
Articulated power steering | |
Pneumatic drum brakes | |
Cruiser Cab standard with air-conditioning. | |
Hydraulics | |
|---|---|
Type | closed center load sensing |
Valves | 4 |
Pump flow | 36 gpm
136.3 lpm |
Steering flow | 35 gpm
132.5 lpm |
Dimensions & Tires | |
|---|---|
Wheelbase | 150 inches
381 cm |
Weight | 40000 lbs
18144 kg |
Front tire | 24.5-32 |
Rear tire | 24.5-32 |
Full dimensions and tires ...  | |
Electrical | |
|---|---|
Ground | negative |
Charging system | alternator |
Charging amps | 75 |
Battery volts | 12 |
References | |
|---|---|
 | |
400/30 400/20 published in 1978, by Big Bud | |
Size Us Up published in 1979, by Big Bud |
Engine
Engine Detail — 736 ci / 12.1 L Diesel
Manufacturer | Detroit Diesel 8V-92T |
Configuration | turbocharged diesel, 8-cylinder, liquid-cooled |
Displacement | 736 ci
12.1 L |
Bore/Stroke | 4.84x5.00 inches
123 x 127 mm |
Power | 400 hp
298.3 kW |
Compression | 19:1 |
Rated RPM | 2100 |
Starter | electric |
Starter volts | 24 |
Transmission
Transmission — Fuller Roadranger RT 12513
Transmission | Fuller Roadranger RT 12513 |
Type | gear |
Gears | 12 forward and 2 reverse |
 | |
Dimensions
Big Bud 400/20 Tires | |
|---|---|
Ag front | 24.5-32 |
Ag rear | 24.5-32 |
Ag front | 30.5-32 |
Ag rear | 30.5-32 |
Dimensions | |
|---|---|
Wheelbase | 150 inches
381 cm |
Length | 267.6 inches
679 cm |
Width | 120 inches
304 cm |
Height (cab) | 144.5 inches
367 cm |
Height (exhaust) | 156 inches
396 cm |
Shipping weight | 40000 lbs
18144 kg |
Max weight | 50000 lbs
22680 kg |
Ground clearance | 14.5 inches
36 cm |
Recommended Implements & Sizing Guide
Engineering recommendations for Big Bud 400/20 based on its 400 HP power envelope and ASAE agricultural standards.
| Implement & Operation | Recommended Size | Workload Rating | Engineering Notes |
|---|---|---|---|
Moldboard PlowPrimary Tillage | 8+ Bottom On-Land Hitch8+ 铧重型机外牵引犁 | Commercial / Field Scale | High horsepower articulated/4WD field plowing. |
Rotary Cutter / MowerMowing & Clearing | 15 to 20 ft Batwing4.6 - 6.1 m 宽幅折叠翼 | Commercial / Field Scale | Large commercial field and roadside mowing operations. |
Rotary TillerSeedbed Prep | 90 to 120 in Heavy Duty230 - 300 cm 重型旋耕机 | Commercial / Field Scale | Deep intensive seedbed preparation for commercial row crops. |
Disc HarrowSecondary Tillage | 24 to 36 ft Heavy Duty Field Disc7.3 - 11.0 m 超宽重型整地耙 | Commercial / Field Scale | Broad-acre grain tillage for high-drawbar tractors. |
Hay BalerHay & Forage | Large Square Baler (3x4 or 4x4)大方捆商用打捆机 (1.2x1.2 m) | Commercial / Field Scale | High-capacity commercial forage harvesting (1000 RPM PTO). |
Sizing & Soil Condition NoteActual implement sizing varies depending on local soil conditions (heavy clay vs sandy loam), field slope, and operating speed. Heavy tillage implements may require front ballast weights and wheel weights.
Fluids, Capacities & Working Autonomy
Standard fluid requirements, service intervals, and continuous runtime estimates for Big Bud 400/20.
Estimated Continuous Field Runtime: 26.4 hrs
Approximately 26.4 hours of continuous field operation at ~75% rated power on a full tank (550 gal / 2082 L).
Estimated 75% Load Fuel Burn~20.8 gal/hr (78.7 L/hr)
Engine Crankcase Oil
SAE 15W-40 (Heavy Duty Diesel)
Standard Spec: API CK-4 / CJ-4 Heavy Duty
Service Interval: 150 – 250 Hours
Transmission & Hydraulic System
UTTO (Universal Tractor Transmission Oil)
Standard Spec: ISO VG 46 / 68 (Wet Brake & Trans Compatible)
Service Interval: 600 – 1000 Hours
Engine Cooling System
50/50 Ethylene Glycol Pre-mix
Standard Spec: ASTM D6210 / Heavy-Duty OAT Antifreeze
Service Interval: 2 Years / 1500 Hours
Big Bud 400/20 Specification Unit Converter
Convert power, fluid capacities, and operating weights between metric and imperial standards for Big Bud 400/20.
Converted Equivalents:
Horsepower (HP)400 hp
Kilowatts (kW)298.3 kW
Metric Horsepower (PS / CV)405.5 PS
Direct Competitor Comparison
Compare Big Bud 400/20 against same-era industry alternatives in the same horsepower class.
Current Model
Big Bud
Big Bud 400/20
Engine Power:Diesel (listed): 400 hp / 298.3 kW
★ Baseline Reference
Related models
Big Bud HN320
- Power:
- 320
- Production years:
- 1976 - 1978
Big Bud HN350
- Power:
- 350
- Production years:
- 1973 - 1978
Big Bud KT350
- Power:
- 350
- Production years:
- 1975 - 1975
Big Bud 360/10
- Power:
- 360
- Production years:
- 1979 - 1980
Big Bud 360/30
- Power:
- 360
- Production years:
- 1979 - 1981