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Kubota BX2200, BX2230, BX2350, BX22 - Transmission

Kubota BX2200, BX2230, BX2350, BX22 - Hydrostatic Transmission

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

Pump and Motor

1 - Swashplate, 2 - Piston, 3 - Cylinder, 4 - Oil, 5 - Cylinder, 6 - Piston, 7 - Swashplate, A - Pump, B - Motor

The hydrostatic transmission consists of variable displacement piston pump, fixed displacement piston motor and valve system. Pump and motor cylinder, each containing pistons, are connected by lines. Cylinders and lines are filled with oil. Pistons ride against swashplates (1) and (7) located in pump (A) and motor (B). In the pump (A), as the cylinder (3) rotates, pistons (2) move across the sloping face of swashplate (1) and slide in or out of their cylinder bores. The oil (4), forced out by the pump pistons (2), causes the motor pistons (6) to slide out of their cylinder bores. In the motor (B), sliding out of the cylinder (5) and moving across the sloping face of swashplate (7), the pistons (6) rotate the cylinder (5).

Charge Relief Valve

1 - Charge Relief Cone, 2 - Plug, 3 - Spring

While pumped and filtered oil flows into the main oil circuit through the check and high pressure relief valves, and excessive oil passes to the housing through the charge relief valve. Oil temperature - 50C (122F). Valve operating pressure - 294 to 490 kPa (42.7 to 71.1 psi).

Check and High Pressure Relief Valve

1 - Relief Valve, 2 - Check Valve, 3 - Relief Valve, 4 - Relief Spring, 5 - Check Spring

The check and high pressure relief valves monitor the oil pressure in each line of the main oil circuit. In neutral, both check valves are open and charging oil enters into the main oil circuit through the valves. At normal operation, the check valve in the high pressure side is closed and it pushes and opens the another one. When excessively high pressure is built up in one line, the high pressure relief valve located in this line is open and the oil flows into another line. Oil temperature - 50C (122F). Relief valve operating pressure - 13.7 MPa (1991 psi).

Kubota BX2200, BX2230, BX2350, BX22 Tractor - Power Take-Off System

PTO Clutch and Valve

1-PTO Select Gear, 2-PTO Clutch Pack, 3-Rear PTO Shaft, 4-Transmission Case, 5-Front Cover, 6-PTO Clutch Valve, 7-PTO Clutch Arm, 8-PTO Relief Valve, 9-Oil Filter Cartridge, A-To Mid-PTO Shaft, B-Connected to PTO Relief Valve, C-From Power Steering Controller, D-To Hydrostatic Transmission

Kubota BX2200, BX2230, BX2350 tractors equipped with hydraulic independent PTO clutch (wet multi-plates type). Therefore, the engine power could engage or disengage 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 (6) controls the hydraulic oil flow from power steering controller to the PTO clutch pack (2) by operating the PTO clutch lever through linkage.

Power Take-Off Relief Valve

1 - PTO Clutch Valve, 2 - Plug, 3 - Spring, 4 - Steel Ball, A - From Power Steering Controller, B - To Hydrostatic Transmission

Power Take-Off Clutch Engaged

1 - 12T Gear Clutch, 2 - Brake Pressure Plate, 3 - Brake Disc, 4 - Clutch Disc and Pressure Plate, 5 - Clutch Case, 6 - Clutch Piston, 7 - Clutch Shaft, 8 - Transmission Case, 9 - Spring, 10 - Clutch Spline Boss, 11 - PTO Clutch Valve, 12 - PTO Clutch Arm, A - From Power Steering Controller, B - To Hydrostatic Transmission, C - To Mid and Rear PTO Shaft

Power Take-Off Clutch Disengaged

1 - 12T Gear Clutch, 2 - Clutch Spline Boss, 3 - Brake Pressure Plate, 4 - Brake Disc, 5 - Clutch Piston, 6 - Clutch Shaft, 7 - Transmission Case, 8 - Spring, 9 - PTO Clutch Valve, A - From Power Steering Controller, B - To Hydrostatic Transmission, C - To Transmission Case

Kubota BX2200, BX2230, BX2350, BX22 Transmission Troubleshooting

Noise from Transmission - Transmission oil insufficient. Gear worn or broken. Bearings worn.

Gear Slip Out of Mesh - Shift fork spring tension insufficient. Shift fork or shifter worn. Shift fork bent.

Excessive or Unusual Noise at All Time - Improper backlash between spiral bevel pinion and bevel gear. Improper backlash between differential pinion and differential side gear. Bearing worn. Insufficient or improper type of transmission fluid used.

Noise while Turning - Differential pinions or differential side gears worn or damaged. Differential lock binding (does not disengaged). Bearing worn.

Differential Lock Can Not Be Set - Differential lock shift fork damaged. Differential lock shifter mounting pin damaged. Differential lock pin damaged.

Differential Lock Pedal Does Not Return - Differential lock pedal return spring weaken or damaged. Differential lock fork shaft rusted.

Uneven Braking Force - Brake rod unevenly adjusted. Brake disc worn. Actuator warped.

Brake Drags - Brake pedal free travel too small. Ball holes of actuator for uneven wear. Brake pedal return spring weaken or broken. Brake cam rusted.

Poor Braking Force - Brake pedal free travel excessive. Brake disc worn. Actuator warped. Brake cam or lever damaged. Transmission fluid improper.

PTO Clutch Slip - Operating pressure is low. PTO clutch valve malfunctioning. Clutch disc or drive plate excessively worn. Deformation of clutch piston.

PTO Shaft Does Not Rotate - PTO clutch malfunctioning.

PTO Clutch Operating Pressure is Low - Transmission oil improper or insufficient. Relief valve malfunctioning.

PTO Clutch Drags - Brake plate excessive worn. Clutch spring weaken or broken. Deformation of pressure plate or steel plate.

Kubota BX2200, BX2230, BX2350, BX22 - Transmission Disassembling and Assembling

Levers and Mower Lift Arm

1-Mower Lift Arm, 2-Feedback Rod, 3-Rue Ring, 4-Hydraulic Control Lever, 5-Front Wheel Drive Lever, 6-Range Gear Shift Lever

Tap out the spring pin from the range gear shift lever (6) and front wheel drive lever (5), then remove the both levers. Remove the mower lift arm (1) with feedback rod (2). Remove the rue ring (3) and hydraulic control lever mounting bolt and nut, then remove the hydraulic control lever (4).

Neutral Plate and Neutral Switch Stay

Remove the trunnion arm mounting bolt and nut. Remove the neutral plate mounting screws, then remove the neutral plate. Remove the neutral switch stay.

Hydrostatic Transmission Assembly

Remove the hydrostatic transmission assembly from transmission case. Apply oil to the O-rings and take care not to damage them. Apply liquid lock to the thread of hydrostatic transmission mounting screws.

Center Section and Charge Relief Valve

1-Center Section, 2-HST Housing

Remove the center section mounting hex. socket head screws. Tap the center section (1) with soft hammer and separate the center section (1) from the HST housing (2). Cover the splines of each shaft with thin tape to protect the sealing lip of the oil seals. Place a new gasket on the HST housing. Take care not to damage the surface of cylinder blocks, pistons and center section. Charge Relief Valve - Remove the plug and draw out the spring and charge relief cone. Take care not to damage the O-ring on the plug.

Check and High Pressure Relief Valve

1-Plug, 2-Spring, 3-Check and High Pressure Relief Valve Assembly (Forward), 4-Check and High Pressure Relief Valve Assembly (Reverse)

Remove the plug (1) and draw out the spring (2) and check and high pressure relief valve assembly (3), (4). Take care not to damage the O-ring on the plug.

Cylinder Block Assembly and Thrust Ball Bearing

1-Cylinder Block Assembly (Pump Side), 2-Cylinder Block Assembly (Motor Side), 3-Motor Shaft, 4-Thrust Ball Bearing

Remove the cylinder block assembly (pump side) (1). Remove the cylinder block assembly (motor side) (2) with the motor shaft (3). Remove the thrust ball bearing (4). Apply clean transmission oil to thrust ball bearing, cylinder block and piston.

Swashplate and Pump Shaft

1-Thrust Roller Bearing, 2-Swashplate, 3-Pump Shaft, 4-Spacer, 5-Oil Seal, 6-Internal Snap Ring

Remove the swashplate (2) and thrust roller bearing (1) from the HST housing. Remove the internal snap ring (6) and tap out the pump shaft (3), spacer (4) and oil seal (5). Apply clean transmission oil to the thrust roller bearing.

Cradle Bearing, Slot Guide and Trunnion Arm

Remove the slot guide and trunnion arm. Remove the cradle bearing from the HST housing. Apply clean transmission oil to the cradle bearing and trunnion arm. Fasten down the cradle bearing to the HST housing.

Kubota BX2200, BX2230, BX2350, BX22 - Transmission Case Disassembly and Assembly

Levers and Mower Lift Arm

1-Mower Lift Arm, 2-Feedback Rod, 3-Rue Ring, 4-Hydraulic Control Lever, 5-Front Wheel Drive Lever, 6-Range Gear Shift Lever

Tap out the spring pin from the range gear shift lever (6) and front wheel drive lever (5), then remove the both levers. Remove the mower lift arm (1) with feedback rod (2). Remove the rue ring (3) and hydraulic control lever mounting bolt and nut, then remove the hydraulic control lever (4).

Neutral Plate and Neutral Switch Stay

Remove the trunnion arm mounting bolt and nut. Remove the neutral plate mounting screws, then remove the neutral plate. Remove the neutral switch stay.

PTO Select Lever and Control Valve

1-Delivery Pipe, 2-PTO Select Lever, 3-PTO Clutch Rod, 4-PTO Safety Switch Stay, 5-Control Valve

Remove the delivery pipe (1) and PTO clutch rod (3). Tap out the spring pin and remove the PTO select lever (2). Remove the control valve (5) with PTO safety switch stay (4). Apply oil to the O-rings and take care not to damage them.

Hydraulic Pump and Suction Pipe

Remove the hydraulic pump and suction pipe from the transmission case. Do not twist the suction hose. Take care not to damage the O-rings.

Seat Rail Front Stay and Hydrostatic Transmission Assembly

1-Seat Rail Front Stay, 2-Hydrostatic Transmission Assembly, 3-Oil Filter Cartridge

Remove the seat rail front stay (1). Remove the hydrostatic transmission assembly (2) and oil filter cartridge (3). Apply oil to the O-rings and take care not to damage them. Apply liquid lock (Three Bond 1324 or equivalent) to the thread of hydrostatic transmission mounting screws.

Kubota BX2200, BX2230, BX2350, BX22 - Hydraulic Cylinder

Remove the hydraulic cylinder mounting screws and dismount the hydraulic cylinder. Apply liquid gasket to joint face of the transmission case to hydraulic cylinder.

Front Cover

Remove the front cover mounting screws and separate the front cover. Apply liquid gasket to joint face of the transmission case to front cover. The spring pin on the front wheel drive idle shaft and gear pump idle shaft should face upper side. Apply grease to the collar on the front wheel drive shaft. Take care not to damage the O-ring.

PTO Clutch Valve

1-PTO Clutch Sleeve, 2-Internal Snap Ring, 3-PTO Clutch Arm, 4-O-ring, 5-O-ring, 6-PTO Clutch Valve, 7-O-ring, 8-O-ring, 9-PTO Clutch Collar, 10-Internal Snap Ring

Remove the PTO clutch arm (3). Remove the internal snap ring (10), then draw out the PTO clutch collar (9) and PTO clutch valve (6). Remove the internal snap ring (2) and draw out the PTO clutch sleeve (1). Take care not to damage the O-rings.

Front Wheel Drive Shaft and Shift Fork

1-Plate, 2-O-ring, 3-Spring, 4-Steel Ball, 5-Oil Seal, 6-Internal Snap Ring, 7-Front Wheel Drive Shaft, 8-Front Cover, 9-Front Wheel Drive Shift Fork, 10-19T Shifter Gear

Remove the plate (1), then draw out the spring (3) and steel ball (4). Remove the oil seal (5) and internal snap ring (6). Tap out the front wheel drive shaft (7) to the front. Remove the 19T shifter gear (10) and front wheel drive shift fork (9). Take care not to damage the O-ring. Replace the oil seal (5) with new one.

13T Gear, 19T Gear Shaft, Hydraulic Pump Idle Shaft, Mid-PTO Shaft and Mid-PTO Idle Shaft

1 - 13T Gear Assembly, 2 - 19T Gear Shaft Assembly, 3 - Hydraulic Pump Idle Shaft Assembly, 4 - Mid-PTO Idle Shaft Assembly, 5 - Mid-PTO Shaft Assembly

Remove the 13T gear assembly (1), 19T gear shaft assembly (2) and hydraulic pump idle shaft assembly (3). Remove the mid-PTO shaft assembly (5) and mid-PTO idle shaft assembly (4).

Spiral Bevel Gear Shaft, 17T-25T Gear Shaft and Front Wheel Drive Idle Shaft

1 - Range Gear Shift Fork, 2 - Spiral Bevel Gear Shaft Assembly, 3 - Front Wheel Drive Idle Shaft Assembly, 4 - 17T-25T Gear Shaft Assembly

Remove the front wheel drive idle shaft assembly (3) and 17T-25T gear shaft assembly (4). Remove the spiral bevel gear shaft assembly (2) together with range gear shift fork (1). Install all of the above mentioned parts, simultaneously.

Rear Cover, Rear PTO Shaft and Rear PTO Drive Shaft

1-Rear Cover, 2-Rear PTO Shaft Assembly, 3-PTO Select Bolt, 4-Rear PTO Drive Shaft Assembly

Remove the rear cover (1) and rear PTO shaft assembly (2). Remove the PTO select bolt (3) and draw out the spring and steel ball. Remove the rear PTO drive shaft assembly (4). Apply liquid gasket to joint face of the transmission case to rear cover. Apply grease to the lip of oil seal.

Final Gear Shaft and Differential Gear Assembly

Draw out the final gear shaft assembly, differential gear assembly and differential lock shift fork. Take care not to damage the O-ring.

Kubota BX2200, BX2230, BX2350, BX22 - Disassembling Differential Gear Assembly

3 - 66T Final Gear, 4 - Differential Case, 5 - Differential Pinion Shaft, 6 - Differential Side Gear, 7 - Differential Side Gear Washer, 8 - Key, 9 - Differential Pinion, 10 - Differential Pinion Washer, 11 - Differential Side Gear, 12 - Differential Side Gear Washer, 13 - Differential Pinion, 14 - Differential Pinion Washer

Remove the bearing (1), differential lock shifter (2) and 66T final gear (3). Put parting marks on the differential pinions (9), (13) and the differential side gears (6), (11). Tap out the differential pinion shaft (5). Remove the differential pinions (9), (13), differential pinion washers (10), (14), differential side gears (6), (11) and differential side gear washers (7), (12). Install the differential pinion and differential side gear, aligning the parting marks. Lock the differential pinion shaft (5) by setting the key (8).

Brake Disc and Friction Plate

1-Internal Snap Ring, 2-Friction Plate, 3-Actuator, 4-Steel Ball, 5-Brake Disc, 6-Bearing Holder, 7-Cam Lever, 8-External Snap Ring

Remove the internal snap ring (1). Remove the bearing holder (6), brake discs (5), friction plates (2), actuator (3) and steel balls (4). Remove the external snap ring (8), then remove the cam lever. Apply grease to the steel balls. Install the brake discs with their holes deviation at less than 1/3 of the total hole area. When installing the bearing holder, do not forget to install the straight pin. Install the internal snap ring (1) as shown in the figure. (Open end of the snap ring should place bottom side). Take care not to damage the O-ring.

Rear Axle

1-Rear Axle, 2-Oil Seal, 3-Bearing, 4-Internal Snap Ring, 5-External Snap Ring

Remove the oil seal (2), then remove the internal snap ring (4). Tap out the rear axle (1) from transmission case or rear axle cover. Do not apply oil to the outer circumference of the oil seal.

Kubota BX2200, BX2230, BX2350, BX22 Tractor - Transmission Servicing

Clearance between Differential Case and Differential Side Gear

Measure the differential side gear boss O.D. with an outside micrometer. Measure the differential case I.D. with a cylinder gauge and calculate the clearance. If the clearance exceeds the allowable limit, replace faulty parts. Clearance between differential case and differential side gear - 0.050 to 0.151 mm / 0.0020 to 0.0059 in. Allowable limit - 0.30 mm / 0.0118 in. Differential case I.D. - 38.000 to 38.062 mm / 1.4961 to 1.4985 in. Differential side gear O.D. - 37.911 to 37.950 mm / 1.4926 to 1.4941 in.

Clearance between Differential Pinion Shaft and Differential Pinion

Measure the differential pinion shaft O.D. with an outside micrometer. Measure the differential pinion I.D. with a cylinder gauge, and calculate the clearance. If the clearance exceeds the allowable limit, replace faulty parts. Clearance between differential pinion shaft and differential pinion - 0.080 to 0.122 mm / 0.0031 to 0.0048 in. Allowable limit - 0.30 mm / 0.0118 in. Differential pinion I.D. - 20.060 to 20.081 mm / 0.7898 to 0.7906 in. Differential pinion shaft O.D. - 19.959 to 19.980 mm / 0.7858 to 0.7866 in.

Backlash between Differential Pinion and Differential Side Gear

Secure the differential case with a vise. Set the dial indicator (lever type) with its finger on the tooth of the differential side gear. Press differential pinion and side gear against the differential case. Hold the differential pinion and move the differential side gear to measure the backlash. If the backlash exceeds the allowable limit, adjust with differential side gear shims. Backlash between differential pinion and differential side gear - 0.15 to 0.30 mm / 0.0059 to 0.0118 in. Allowable limit - 0.40 mm / 0.0157 in.

Side Clearance of Spiral Bevel Pinion Shaft

Temporary assemble the spiral bevel pinion shaft and front cover to the transmission case. Set the dial indicator (lever type) with its finger on the end of spiral bevel pinion shaft. Move the spiral bevel pinion shaft back and forth to each end and measure the side clearance. If the side clearance exceeds the factory specifications, adjust with the shim at front end of spiral bevel pinon shaft. Side clearance of spiral bevel pinion shaft - 0.1 to 0.3 mm / 0.0039 to 0.0118 in.

Backlash between Spiral Bevel Pinion Shaft and Spiral Bevel Gear

Temporary assemble the spiral bevel pinion shaft, and properly adjust the side clearance. Place fuses between spiral bevel pinion shaft and spiral bevel gear. Assemble the axle cover assembly, and turn the rear axle. Remove the axle cover assembly, and take out the fuses. Measure the thickness of fuses with an outside micrometer. If the measurement is not within the factory specifications, adjust with shims. Backlash between spiral bevel pinion shaft and spiral bevel gear - 0.1 to 0.3 mm / 0.0039 to 0.0118 in.

Flatness of Actuator and Bearing Holder

Place a straightedge of 150 mm (5.91 in.) or more in length on the contacting surface of the actuator and the bearing holder. Inspect the friction surface of the actuator and the bearing holder with the straightedge, and determine if a 0.30 mm (0.0118 in.) feeler gauge will fit on the part of wear. If it will fit, resurface. Flatness of actuator and bearing holder - Allowable limit 0.30 mm / 0.0118 in.

Height of Cam Plate and Ball

Measure the height of the cam plate with the ball installed. If the measurement is less than the allowable limit, replace the cam plate and balls. Inspect the ball holes of cam plate for uneven wear. If the uneven wear is found, replace it. Height of cam plate and ball - 22.89 to 22.99 mm / 0.9012 to 0.9051 in. Allowable limit - 22.40 mm / 0.8819 in.

Brake Disc and Friction Plate Wear

Measure the brake disc thickness and the friction plate thickness with an outside micrometer. If the thickness is less than the allowable limit, replace it. Brake disc thickness - 3.3 to 3.5 mm / 0.130 to 0.138 in. Allowable limit - 3.0 mm / 0.118 in. Friction plate thickness - 1.92 to 2.08 mm / 0.0756 to 0.0819 in. Allowable limit - 1.52 mm / 0.0598 in.

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