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Kubota B1502, B1610, B4200 - Mechanical Transmission

Kubota B1502, B1610, B4200 Transmission Troubleshooting

Problem - Noise from Transmission

Transmission oil insufficient - Refill.
Gear worn or broken - Replace.
Improper backlash between ring gear and spiral bevel pinion shaft - Adjust.
Improper backlash between differential pinion and differential side gear - Adjust.
Bearings worn - Replace.

Problem - Gear Slip out of Mesh

Shift fork spring tension insufficient - Replace.
Shift fork or shifter worn - Replace.
Shift fork bent - Replace.

Problem - Differential Lock Cannot Be Set

Differential lock pedal play excessive - Adjust.
Differential lock shift fork broken - Replace.
Differential lock clutch broken - Replace.

Problem - Differential Lock Pedal Does Not Return

Differential lock spring broken or fall - Replace or Assemble.
Differential lock spring tension insufficient - Replace.

Kubota B1502, B1610, B4200 Single Plate Clutch - Checking and Adjusting

Clutch Pedal Play

Depress the clutch pedal by hand, and measure the amount of pedal movement. If the measurement is not within the factory specifications, adjust the play by turning the rod. Clutch pedal play - 20 to 30 mm 0.79 to 1.18 in.

Clutch Pedal Traveling

Measure the distance between clutch rod and clutch adjusting screw. If the measurement is not within the factory specifications, adjust it with the clutch adjusting screw. After adjustment, secure the clutch adjusting screw with the lock nut. Distance between clutch rod and clutch adjusting screw - 11 to 13 mm 0.43 to 0.51 in.

Clearance between Safety Switch and Clutch Rod

Measure the clearance between safety switch and clutch rod with a feeler gauge. If the clearance is not within the factory specifications, adjust the mounting position of switch. Clearance between safety switch and clutch rod - 4.5 to 5.0 mm 0.177 to 0.197 in.

Kubota B1502, B1610, B4200 Single Plate Clutch - Disassembly And Assembly

Separation of Clutch Assembly

1 - Clutch center tool, 2 - Clutch disc boss

Separate the clutch assembly from the flywheel. Install the clutch assembly with the clutch center tool (1). Face the longer end of the clutch disc boss (2) rearward.

Clutch Rod and Clutch Release Fork

Remove the front step frame LH. Remove the cotter pin at the end of the clutch rod, and remove the clutch release fork and clutch rod. Set the fork in the correct direction.

Release Bearing Holder

Remove the spring mounting screw and spring. Remove the grease nipple. Pull out the release bearing holder toward the front of the housing.

Kubota B1502, B1610, B4200 Tractor - Single Plate Clutch Service

Backlash between Clutch Disc and Propeller Shaft

Mount the clutch disc onto the propeller shaft. Fix the rule on the housing. Hold the propeller shaft so that it does not rotate. Slightly move the disc and measure the displacement around disc edge. If the measurement exceeds the allowable limit, replace clutch disc. Displacement around disc edge (Allowable limit) - 2.0 mm 0.079 in.

Clutch Disc Wear

Measure the depth from clutch disc surface to the top of rivet at least 10 points with a depth gauge. If the depth is less than the allowable limit, replace. If oil is sticking to the clutch disc, or disc surface is carbonized, replace clutch disc. Depth to rivet top (Allowable limit) - 0.3 mm 0.012 in.

Pressure Plate Flatness

Place a straightedge on the pressure plate and measure clearance with a feeler gauge at several points. If the clearance exceeds allowable limit, replace pressure plate. When the pressure plate is worn around its outside and its inside surface only is in contact with the straightedge, replace it even if the clearance is within the allowable limit. Clearance between pressure plate and straight edge (Allowable limit) - 0.2 mm 0.008 in.

Checking Pressure Plate and Diaphragm

Check the pressure plate and if scratched on its surface, correct with sandpaper or replace it. Check the diaphragm for cracks and scratches. If defects are found, replace it.

Checking Clutch Release Bearing

Check the clutch release bearing. If surface is worn excessively, or abnormal sounds occur, replace it.

Kubota B1502, B1610, B4200 Transmission Case - Disassembling And Assembling

Shaft Cover 1

Remove the shaft cover 1. Be sure to replace the gasket with a new one.

1st Shaft

1 - Bearing, 2 - 1st Shaft, 3 - Bearing, 4 - Bearing, 5 - 2nd Shaft, 6 - 29T Gear, 7 - Cover Spacer, 8 - Gasket

Remove the bearing (1) on the 1st shaft (2) with a special-use puller set. Remove the bearing (4) and 29T gear (6) on the 2nd shaft (5) with a special-use puller set. Remove the 1 st shaft with the cover spacer (7). Be sure to replace the gasket (8) with a new one.

Fork Shaft and Shift Fork

Remove the shaft lock screw. Screw M8 screw (pitch 1.25 x 70 mm long, pitch 1.25 x 2.76 in. long) into the fork shaft, and tap out it to the rear. Remove the shift fork. Install the fork shaft with the groove (4) facing the differential gear case.

Spiral Bevel Pinion Shaft

1 - 24T gear, 2 - Collar, 3 - Needle Bearing, 4 - Spacer, 5 - Shim, 6 - Bearing, 7 - 13T-32T Gear, 8 - External Snap Ring, 9 - Collar, 10 - Stop Collar, 11 - Bearing, 12 - Bearing, 13 - Spiral Bevel Pinion Shaft, 14 - 16T Gear, 15 - Pinion Collar, 16 - Drum

Remove the rod and drum (16). Draw out the spiral bevel pinion shaft (13) Remove the 24T gear (1) (4WD type only).

4th Shaft

1 - Bearing, 2 - 30T Gear, 3 - 13T-17T Gear, 4 - Bearing, 5 - 4th Shaft, 6 - External Snap Ring, 7 - 19T Gear, 8 - Collar, 9 - Bearing

Remove the external snap ring (6). Set a wood piece, and tap out the 4th shaft (5) to the rear to remove the bearing (1). Remove the 30T gear (2) and 13T-17T gear (3), and pull out the 4th shaft(5).

2nd Shaft

1 - Bearing, 2 - 2nd Shaft with 13T Gear, 3 - 29T Gear, 4 - 13T Gear, 5 - 17T Gear, 6 - Bearing

Draw out the 2nd shaft (2) to the rear.

Reverse Shaft

1 - Oil Seal, 2 - Internal Snap Ring, 3 - Reverse Shaft (4WD), 4 - Collar, 5 - 16T-20T Gear, 6 - Needle Bearing, 7 - Bearing, 8 - Internal Snap Ring, 9 - Bearing, 10 - Reverse Shaft (2WD), 11 - Collar 1, 12 - Collar,

Remove the internal snap ring (8), and tap out the reverse shaft (3 or 10) to the rear.

3rd Shaft

1 - Internal Snap Ring, 2 - Shim, 3 - Bearing, 4 - 17T-13T Gear, 5 - 3rd Shaft, 6 - Bearing, 7 - Internal Snap Ring

Remove the internal snap ring (7). Set a wood piece, and tap out the 3rd shaft (5) to the rear to remove the bearing (3). Remove the 17T-13T gear (4) and pull out the 3rd shaft (5).

PTO Fork Shaft and Mid-PTO

Tap out the PTO fork shaft to the front. The 19T Gear is used for the gear transmission instead of the 24T Gear.

Kubota B1502, B1610, B4200 Tractor - Transmission Case Servicing

Checking Bearing

Hold the inner race, and push and pull the outer race in all directions to check for wear and roughness. Apply transmission oil to the bearing, and hold the inner race. Then, turn the outer race to check rotation. If there is any defect, replace it.

Gear Backlash

Set a dial indicator (lever type) with its finger on the tooth surface. Move the gear to measure the backlash, while holding the mating gear. If the measurement exceeds the allowable limit, replace it. Gear backlash - 0.10 to 0.20 mm (0.004 to 0.008 in). Allowable limit - 0.4 mm (0.006 in).

Clearance between Shift Fork and Shift Gear Groove

Place the shift fork in the shift gear groove and measure the clearance with a feeler gauge. If the clearance exceeds the allowable limit, replace it. Clearance between shift fork and shift gear groove - 0.10 to 0.35 mm (0.004 to 0.014 in). Allowable limit - 0.5 mm (0.020 in).

Clearance between 16T-20T Gear and Reverse Shaft

Measure the 16T-20T gear I.D. with an inside micrometer, and then reverse shaft O.D. with an outside micrometer. Measure the O.D. of two needles in the needle bearing with an outside micrometer. Clearance is the difference between the gear I.D. and the sum of shaft O.D. and two needle O.D. If the clearance exceeds the allowable limit, replace. Clearance between 16T-20T gear and reverse shaft - 0.007 to 0.0045 mm (0.0003 to 0.0018 in). Allowable limit - 0.1 mm (0.0039 in). Reverse shaft O.D. - 21.967 to 21.980 mm (0.8648 to 0.8654 in). 16T-20T gear I.D. - 25.987 to 26.000 mm (1.0231 to 1.0236 in). Needle O.D. - 1.994 to 2.000 mm (0.0785 to 0.0787 in).

Kubota B1502, B1610, B4200 Differential Gear Case - Disassembly And Assembly

Differential Assembly

1 - Shim, 2 - Differential Side Gear, 3 - Differential Pinion Collar, 4 - Differential Pinion, 5 - Thrust Collar, 6 - Differential Side Gear, 7 - Ring Gear Bushing, 8 - Shim, 9 - Differential Bearing Holder (RH), 10 - Differential Side Shim, 11 - Differential Pinion Shaft, 12 - Differential Pinion Collar, 13 - Differential Pinion, 14 - Bearing, 15 - Differential Case, 16 - Ring Gear, 17 - Bearing, 18 - Differential Side Shim, 19 - Differential Bearing Holder (LH)

Remove the left and right differential bearing holders (19), (9). Take out the differential assembly from the differential gear case. Install the differential assembly, noting the number of differential side shims (10), (18).

5th Shaft

Remove the external snap ring, and remove the drum and spring. Remove the rear cover mounting screws. Remove the 5th shaft with the PTO shaft.

РТО Shaft

1 - Rear Cover, 2 - 22T Gear, 3 - Taper Roller Bearing, 4 - Washer, 5 - Lock Washer, 6 - Screw, 7 - PTO Shaft, 8 - Bushing, 9 - PTO Collar, 10 - PTO Shim, 11 - Taper Roller Bearing, 12 - PTO Collar

Flatten the lock washer (5). Remove the screw (6), plain washer, lock washer (5), washer (4) and straight pin. Tap out the PTO shaft (7) to the rear. Replace the lock washer with a new one, be sure to adjust the turning torque of PTO shaft. Lock the screw with the lock washer after adjusting the turning torque. Tightening torque Screw - 18.6 to 32.4 Nm (13.7 to 23.9 ft-lbs).

Kubota B1502, B1610, B4200 Tractor - Differential Gear Case Service

Initial Turning Torque of PTO Shaft

1 - Taper Roller Bearing, 2 - 22T Gear, 3 - PTO Collar, 4 - Taper Roller Bearing, 5 - PTO Collar, 6 - Bushing, 7 - PTO Bearing Collar, 8 - Oil Seal, 9 - PTO Shaft, 10 - Screw, 11 - Plain Washer, 12 - Lock Washer, 13 - Washer, 14 - Straight Pin, 15 - Shim

Tighten the screw (10) to the specified torque (18.6 to 32.4 Nm, 13.7 to 23.9 ft-lbs). Install the PTO shaft to the rear cover, and install it to the differential gear case. Screw the screw (M 10 x Pitch 1.25) in PTO shaft (9), and set a torque wrench to it. Turn the PTO shaft with a torque wrench to measure the initial turning torque. If the initial turning torque is not within the factory specifications, adjust the turning torque with the shims (15). Initial turning torque - 0.49 to 1.47 Nm (0.36 to 1.08 ft-lbs). Thickness of shims: 0.3 mm (0.012 in.), 0.4mm (0.016 in.), 0.5 mm (0.020 in.). Lock the screw (10) with the lock washer (12) after adjusting the turning torque.

Backlash between Ring Gear and Spiral Bevel Pinion Shaft

Set a dial indicator (lever type) on the ring gear. Measure the backlash by fixing the spiral bevel pinion shaft and moving the ring gear by hand. When the backlash is too small, decrease the number of shims in the side of the ring gear, and insert the removed shims in the opposite side. When the backlash is too large, decrease the number of shims in the side of the differential case, and insert the removed shims in the opposite side. Adjust the backlash properly by repeating the above procedure. Backlash between ring gear and spiral bevel pinion shaft - 0.1 to0.2 mm (0.004 to 0.008 in). Allowable limit - 0.4 mm (0.016 in).

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