Specifications, Service and Repair of Farm and Lawn Tractors

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Kubota BX1860, BX2360, BX2660 - Transmission System


Kubota BX1860, BX2360, BX2660 Tractor - Hydrostatic Transmission



1. Check and High Pressure Relief Valve, 2. Trunnion Arm, 3. Center Section, 4. Piston Spring, 5. Piston, 6. Thrust Ball Bearing, 7. Swashplate, 8. Cradle Bearing, 9. Spring, 10. Cir-Clip, 11. Spring, 12. Cir-Clip, 13. Thrust Ball Bearing, 14. Cylinder Block (Motor), 15. Plug, 16. Motor Shaft, 17. Needle Bearing, 18. Ball Bearing, 19. Pump Shaft, 20. Cylinder Block (Pump), 21. Charge Relief Valve

Hydraulic Pump Drive Gear Section



1. Hydrostatic Transmission Pump Shaft, 2. Spline Boss, 3. Idle Gear, 4. Hydraulic Pump Drive Gear Shaft, 5. Hydraulic Pump Drive Gear, 6. Hydraulic Pump Drive Gear Shaft, 7. Hydraulic Pump, 8. Flow Priority Valve, 9. Relief Valve (3-Point Hitch), 10. Transmission Case

The hydraulic pump (7) is mounted to the transmission case (10) and driven by the hydraulic pump drive gear (5). The spline boss (2) mounted on the HST pump shaft drives the hydraulic pump drive gear (5) mounted on the hydraulic pump drive gear shaft (4) through the idle gear (3).

Kubota BX1860, BX2360, BX2660 - Transmission Oil Flow

Neutral

When the speed control pedal is in neutral, the variable swashplate is not tilted as shown in figure above. The pump pistons only rotate with cylinder block without reciprocating. Since the oil is not being pumped to the motor, the cylinder block in the motor is stationary and the output shaft does not move.



1. Cylinder Block (Pump), 2. Swashplate, 3. Piston, 4. Cylinder Block (Motor), 5. Check and High Pressure Relief Valve (Forward), 6. Check and High Pressure Relief Valve (Reverse), 7. High Pressure Relief Port Plug (Forward), 8. Charge Relief Valve, 9. High Pressure Relief Port Plug (Reverse), 10. PTO Clutch Valve, 11. PTO Relief Valve, 12. Oil Filter Cartridge, 13. Power Steering Controller, 14. Hydraulic Pump, 15. Flow Priority Valve (Hydraulic Control Valve), 16. Position Control Valve, 17. Oil Strainer, 18. Transmission Case, A. A Port, B. B Port, C. C Port, D. D Port, X. High Pressure, Y. Low Pressure, Z. Free Oil

Forward

When the speed control pedal is stepped on and in forward, the variable swashplate is tilted. As the pump cylinder block rotates with the input shaft, oil is forced out of pump port B at high pressure. As pressure oil enters motor port D, the pistons, which align with port D, are pushed against the swashplate and slide down the inclined surface. Then the output shaft rotates with the motor cylinder block. This drives the machine forward and the angle of pump swashplate determines the output shaft speed. As the motor cylinder block continues to rotate, oil is forced out of motor port C at low pressure and returns to the pump.

Reverse

When the speed control pedal is stepped on and in reverse, the variable swashplate is tilted. As the pump cylinder block rotates with the input shaft, oil is forced out of pump port A at high pressure. As pressure oil enters motor port C, the pistons, which align with port C, are pushed against the swashplate and slide down the inclined surface. Then the output shaft rotates with the motor cylinder block. This drives the machine rearward and the angle of pump swashplate determines the output shaft speed. As the motor cylinder block continues to rotate, oil is forced out of motor port D at low pressure and returns to the pump.

Relief (Reverse)

When the speed control pedal is in reverse, the variable swashplate is tilted. As the pump cylinder block rotates with the input shaft, oil is forced out of pump port A at high pressure. As pressure oil enters motor port C, the pistons, which align with port C, are pushed against the swashplate and slide down the inclined surface. Since the oil pressure in the check and high pressure relief valve (Reverse) increase, the high oil pressure opens the check and high pressure relief valve (Reverse) and the flows through the charge relief valve to the transmission case. Then the output shaft rotates with the motor cylinder block. This drives the machine rearward and the angle of pump swashplate determines the output shaft speed. As the motor cylinder block continues to rotate, oil is forced out of motor port D at low pressure and returns to the pump.

Kubota BX1860, BX2360, BX2660 - Hydrostatic Transmission Linkage

Control Linkage



1. Neutral Spring, 2. Trunnion Arm, 3. Cruise Rod, 4. Brake Pedal, 5. Speed Control Pedal, 6. Parking Plate, 7. Cruise Arm, 8. Cruise Lock, 9. Cruise Lock, 10. HST Pedal Link, 11. Speed Change Rod, 12. Damper, 13. Arm

The speed control pedal (5) and the trunnion arm are linked with the HST pedal link (10) and the speed change rod (11). As the front of the pedal is depressed, the swashplate connected to the trunnion arm (2) rotates and forward travelling speed increases. Depressing the rear end increases reverse speed. The trunnion arm (2) is returned to neutral position by the neutral arm and the tension of neutral spring. At the same time, the swashplate is returned to neutral, when the pedal is released. The damper (12) connected to the HST pedal link (10) restricts the movement of the linkage to prevent abrupt operation or reversing. Moreover, the feeling of the dynamic braking can be adjusted by changing the arm (13) position of damper (12).

Speed Set Linkage



1. Speed Set Rod, 2. Brake Pedal, 3. Speed Control Pedal, 4. Parking Brake Lock Pedal, 5. Cruise Lock, 6. Cruise Lock, 7. Cruise Arm, 8. HST Pedal Link, 9. Speed Change Rod, 10. Damper, 11. Trunnion Arm, 12. Release Plate, 13. Brake Rod, A. Speed Set Rod OFF, B. Speed Set Rod ON, C. Speed Control Pedal Forward, D. Cruise Lock Locked

When pushing and holding the speed set rod (1) and depressing the speed control pedal (3), the desired speed is set. When pushing the speed set rod (1), the cruise arm (7) is rotated counter clockwise. When depressing the speed control pedal (3) forward, the HST pedal link clockwise. Since both the cruise lock (5) of the cruise arm (7) and the cruise lock (6) of HST pedal link (8) are locked, the speed control pedal (3) is held at a selected position.

When the Brake Pedal is Depressed



1. Brake Rod, 2. Speed Control Pedal, 3. Parking Brake Lock Pedal, 4. Brake Pedal, 5. Release Plate, 6. Speed Set Rod, 7. Cruise Arm, 8. Cruise Lock, 9. Cruise Lock, 10. HST Pedal Link, 11. Speed Change Rod, 12. Trunnion Arm, A. Brake Pedal Depressed, B. Release Plate Pushed Down, C. Cruise Rod Pushed Up, D. Cruise Arm Rotates Clockwise, E. HST Pedal Link Pushed Up

When the brake pedal (1) is depressed, the release plate (5) located under the brake pedal (1) is pushed down. Since the release plate (5) rotates, the HST pedal link (10) is pushed up. The lock between the cruise lock (9) of the HST pedal link (10) and the cruise lock (8) of the cruise arm (7) is released. The speed control pedal (2) is not held at a selected position. Since the spring pulls the speed set rod (6) upward, the speed set rod (6) is pushed up.

Kubota BX1860, BX2360, BX2660 Transmission - Range Gear Shift Section



1. 25T Gear, 2. 17T Gear, 3. Spiral Bevel Pinion Shaft, 4. 16T-24T Shifter Gear, L. Low Range, H. High Range

Two kinds of power flow are selected by operating the range gear shift lever to shift the 16T-24T shifter gear (4) on the spiral bevel gear shaft (3).

Low Range: 17T Gear Shaft (2) - Shifter Gear (24T) (4) - Spiral Bevel Pinion Shaft (3).

High Range: 25T Gear (1) - Shifter Gear (16T) (4) - Spiral Bevel Pinion Shaft (3).

Kubota BX1860, BX2360, BX2660 - Front Wheel Drive Section



1. Front Wheel Drive Shaft, 2. 19T Shifter Gear, 3. Spiral Bevel Pinion Shaft, 4. 12T Gear, 5. 13T-25T Gear Shaft, A. Front Wheel Drive Engaged

2WD or 4WD drive is selected by changing the position of 19T shifter gear (2) with the front wheel drive lever. Front Wheel Drive “Disengaged” - When the front wheel drive lever is set to “Disengaged” position, the 19T shifter gear (2) is neutral and power is not transmitted to the front wheel drive shaft (1). Front Wheel Drive “Engaged” - When the front wheel drive lever is set to “Engaged” position, the 19T shifter gear (2) slides to the right to engage with 13T-25T gear shaft (5). Therefore, the power from spiral bevel pinion shaft (3) is transmitted to the front wheel drive shaft (1) through the gears.

Kubota BX1860, BX2360, BX2660 Tractor - Differential

Differential Gears



1. Differential Case, 2. Differential Pinion, 3. 37T Spiral Bevel Gear, 4. 10T Final Gear Shaft, 5. Differential Side Gear, 6. Differential Pinion Shaft, 7. 66T Final Gear, 8. Differential Pinion, 9. Differential Side Gear

Differential Lock



1. Rear Axle, 2. Differential Lock Shifter, 3. Differential Case, 4. Differential Pinion, 5. Rear Axle, 6. Differential Lock Arm, 7. Differential Lock Shaft, 8. Differential Lock Shift Fork, 9. Differential Side Gear, 10. Differential Pinion Shaft, 11. Differential Pinion

Kubota BX1860, BX2360, BX2660 - Brake Section



1. Rear Axle LH, 2. Final Gear Shaft, 3. Shim, 4. Bearing Holder, 5. Friction Plate, 6. Actuator, 7. Steel Ball, 8. Cam Lever, 9. O-ring, 10. Rear Axle RH, 11. Brake Disc, 12. Internal Cir-Clip, 13. Brake Pedal, 14. Brake Rod, 15. Parking Brake Lock Pedal, A. Connects with Brake Cam Lever and Brake Rod

The mechanical wet disc brakes are used for the travelling brake. The brake is operated by the brake pedal (13) through the mechanical linkages and provide stable braking and require little adjustment. The brake body is incorporated in the transmission case and axle cover filled with transmission oil. For greater braking force, four brake discs (11) are provided at the brake shaft, and the friction plates (5) fixed to the transmission case is arranged between the brake discs (11).

Travelling Brake - When the brake pedal (13) is depressed, the brake rod pulls the brake cam lever (8). Therefore, the cam plates also moves and rides on the steel balls set in the grooves of the transmission case to press the brake disc, the final gear shaft is braked by the frictional force generated by the cam plate and brake disc.

Parking Brake - When the parking brake is applied, the brake pedal (13) is locked by the parking brake lock pedal (15).

Kubota BX1860, BX2360, BX2660 Tractor - PTO System

PTO Clutch and Valve



1. PTO Select Gear, 2. PTO Clutch Pack, 3. Rear PTO Shaft, 4. Transmission Case, 5. PTO Clutch Valve, 6. PTO Clutch Relief Valve, 7. Oil Filter Cartridge, A. From HST Pump Shaft, B. To Mid-PTO, C. From Power Steering Controller, D. To Hydrostatic Transmission

Kubota BX1860, BX2360, BX2660 tractors equipped with hydraulic independent PTO clutch (wet multi-plates type). Therefore, the engine power engages or disengages to the PTO shafts without stopping the tractor movement. The PTO clutch pack (2) has four clutch discs, four drive plates, pressure plate, clutch piston and so on. The clutch piston is actuated by hydraulic oil flow from the power steering controller. The PTO clutch valve (5) controls the hydraulic oil flow from power steering controller to the PTO clutch pack (2) by operating the PTO clutch lever through the linkage.

PTO Clutch Relief Valve



1. Plug, 2. O-ring, 3. Spring, 4. Steel Ball, 5. PTO Clutch Valve, 6. HST Charge Relief Valve, 7. PTO Clutch Relief Valve, 8. Poppet, A. From Power Steering Controller, B. To Hydrostatic Transmission, C. To PTO Clutch Valve, a. Old Type, b. New Type

The PTO clutch relief valve is provided to control the PTO operating pressure. When the oil pressure exceed the relief valve setting pressure, relief valve opens and the oil flows into PTO clutch and hydrostatic transmission. Relief valve setting pressure - 490 kPa (71.2 psi).

Mid and Rear PTO Section



1. HST Pump Shaft, 2. 12T Clutch Gear, 3. PTO Clutch Pack, 4. Rear PTO Shaft, 5. 23T Mid PTO Gear, 6. 24T Mid PTO Idle Gear, 7. Mid-PTO Shaft, 8. 28T PTO Select Gear, 9. 11T Gear Shaft

Three kinds of power flow are selected by operating the PTO select lever to shift the PTO select gear (8) on the 11T gear shaft (9).

Mid-PTO Position (A): PTO Clutch Pack (3) - 12T Gear Clutch (2) - PTO Select Gear (8) - 23T Mid PTO Gear (5) - 24T Mid PTO Idle Gear (6) - Mid-PTO Shaft (7).

Rear PTO Position (B): PTO Clutch Pack (3) - 12T Gear Clutch (2) - PTO Select Gear (8) - 11T Gear Shaft (9) - Rear PTO Shaft (4).

Mid and Rear PTO Position A and B at the same time.

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KUBOTA TRACTORS SPECIFICATIONS

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KUBOTA ENGINES DATA AND SERVICE SPECS

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KUBOTA FRONT END LOADERS

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KUBOTA TRACTORS TROUBLESHOOTING
L235 L2501 L2550 L275 L3110
L3301 L35 L3710 L3901 L4310
L5030 M4700 M5700 M6040 M6800
M8200 M8540 M9000 MX5100 MX5200