Problem Solving

Introduction

NOTE: For Specifications with illustrations, make reference to the POWER TRAIN SPECIFICATIONS FOR 931 TRACK-TYPE LOADER, Form No. REG01327. If the Specifications in Form REG01327 are not the same as in he Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

Use this as a reference for the location and correction of problems in the power train. When more checking is necessary, use the 7S8875 or 8M2736 Hydraulic Test Box and the 5P3598 Transmission Test Cover. Locations of the pressure taps, and procedures for testing and adjustment are given in the 931 POWER SHIFT TRANSMISSION TESTING AND ADJUSTING, Form No. REG01326.

Always make visual checks first. Then check the operation of the machine and go on to check with instruments.

Visual Checks

1. Check the oil level in the transmission and in the case of the bevel gear.

2. Check the oil level of the final drives.

3. Check all outside oil lines, connections and outside valves for leakage or damage.

4. Check the linkage for the transmission control and the linkage for the steering and brake control for damage and/or adjustment.

5. Check and make sure the track is not too tight.

6. Check the element in the transmission filter and the screen for foreign matter.

a. Particles that are iron or steel is an indication of damage in the transmission.

b. Fiber particles is an indication of damage to the clutches in the transmission.

c. Particles that are steel and are found in the filter is an indication of pump failure.

d. Particles of bronze is an indication of damage to the torque converter.

e. Particles of rubber is an indication of damage to a seal or a hose.

If you find particles or rubber or metal, all components must be thoroughly cleaned and flushed. Replace all parts that have damage.

Checks During Operation

With the engine running move the selector level to all speed positions. The detents must be felt in all positions.

Operate the machine in each direction and in all speeds. Make note of all noises that are not normal and find their sources. If the operation is not correct, make reference to the CHECK LIST DURING OPERATION for "problems" and "probable causes."

Check List During Operation

Transmission

PROBLEM: Does not operate in any speed or does not engage (slips) in all speeds.

PROBABLE CAUSE:

1. Low oil pressure caused by:

a. Low oil level.

b. Control linkage loose or adjustment not correct.

c. Failure of the oil pump or the pump drive.

d. Air leaks on inlet side of pump.

e. Leakage inside the transmission.

f. Adjustment of the modulating relief valve not correct, or valve does not close.

g. Load piston not closing.

2. Mechanical failure in the transmission.

3. Failure in the torque converter.

4. Failure of the bevel pinion and/or the bevel gear.

PROBLEM: Transmission does not shift.

PROBABLE CAUSE:

1. Low oil level.

2. Low pressure in the clutches.

3. Control linkage loose or adjustment not correct.

PROBLEM: Slow shifting.

PROBABLE CAUSE:

1. Low oil pressure.

2. Adjustment of inside and outside control linkages not correct.

3. Air leakage on inlet side of the pump.

4. Load piston not closing.

PROBLEM: Transmission engages very suddenly (rough shifting).

PROBABLE CAUSE:

1. Adjustment of control linkage not correct.

2. Primary setting of relief valve not correct.

3. Load piston not closing.

4. Valve springs that are weak or have damage.

PROBLEM: Does not operate in one speed or operates in only one speed.

PROBABLE CAUSE:

1. Control linkage loose or adjustment not correct.

2. Discs or plates have wear or damage. Other components of the clutch have damage.

3. Too much leakage at the connections and/or at the piston seals.

4. Clutch plates have damage.

PROBLEM: Transmission does not shift out of speed when the shift lever is moved to NEUTRAL.

PROBABLE CAUSE:

1. Control linkage have damage or adjustment not correct.

2. Clutch not releasing.

PROBLEM: Transmission engages, torque converter stalls and the engine has a load condition. Machine does not move.

PROBABLE CAUSE:

1. Mechanical failure in the transmission.

a. Parts that have damage.

b. A clutch not correctly engaged.

2. Failure of the bevel gear, bevel pinion or transfer gears.

3. Failure of the pinion or gears in the final drive.

PROBLEM: Transmission gets hot.

PROBABLE CAUSE:

1. Bad temperature gauge.

2. Low oil level.

3. Core of oil cooler not completely open.

4. Too much resistance in the engaged clutch.

5. Low oil flow as a result of pump wear or extra leakage in the hydraulic system.

PROBLEM: Pump noise not normal.

PROBABLE CAUSE:

1. Loud sounds at short intervals that give indication that particles are going through the pump is caused by pump cavitation.

2. A constant loud noise is an indication of pump failure.

Torque Converter

PROBLEM: Torque converter gets too hot.

PROBABLE CAUSE:

1. Operation of machine not correct. Constant overload.

2. Bad temperature gauge.

3. Mechanical failure in the torque converter.

4. Too much oil in torque converter housing because of leakage through the torque converter.

5. Supply of oil to the torque converter is low because of:

a. Too much leakage in the transmission.

b. Bad pump.

c. Inlet valve for torque converter not working correctly.

d. Core of oil cooler not completely open.

Steering

PROBLEM: Machine will not turn in either direction.

PROBABLE CAUSE:

1. Linkage loose or adjustment not correct.

2. Low transmission oil pressure.

PROBLEM: Machine goes in either direction with both steering clutches engaged.

PROBABLE CAUSE:

1. Adjustment of steering clutch linkage not correct.

2. Steering clutch plates have wear.

3. Steering clutch springs are broken or have wear.

4. Bolts that hold steering clutch spring broken.

5. Defect in steering control valve.

PROBLEM: Slow steering.

PROBABLE CAUSE:

1. Steering clutch linkage broken or adjustment is not correct.

2. Brake lining have wear.

3. Defect in steering control valve or hoses.

4. Low transmission oil pressure.

Final Drive And Undercarriage

Sprocket Shaft Bearings For The Final Drive

To check bearing adjustment, put a four or five foot bar between the track roller frame and the sprocket. If the sprocket shaft bearings are loosen when pushing or pulling with the bar, adjustment is necessary. Do the checking when there are no objects under the track which put weight on the sprocket.

FINAL DRIVE
1. Bearing. 2. Spacer. 3. Bearing. 4. Nuts. 5. Spacer. 6. Sprocket.

1. Separate the track by removing the master pin.

2. Lower the track roller frame.

3. Remove the sprocket (6).

4. Check the torque on the nut (4). Correct torque on nut (4) is 493 ± 49 lb.ft. (68.2 ± 6.8 mkg).

5. Replace bearings (1) and (3) if the torque on nut (4) is correct and there is still end play on the bearings (1) and (3).

6. Replace spacers (2) and (5) if they are worn.

Alignment Of The Front Idler

Use shims (1) and (2) as necessary to make alignment of the front idler and the track roller to .06 in. (1.5 mm).

Use shims (1) and (2) as necessary to keep clearances (A) and (B) to .06 in. (1.5 mm) on each side of the idler.

FRONT IDLER
1. Shims. 2. Shims. A. .06 in. (1.5 mm) dimension on each side of idler. B. .06 in. (1.5 mm) dimension on each side of idler.

Track Adjustment

CHECKING TRACK ADJUSTMENT
A. 11/2 to 2 in. (38 to 55 mm) sag at this point.

Operate the track with a small amount of tension so the amount of wear will not be too much. When the adjustment is correct, there must be 11/2 to 2 in. (38 to 55 mm) sag, dimension (A), measured at a point half way between the track carrier roller and the front idler.

Hydraulic Adjustment

To let all air out of the track adjusting mechanism and to make sure that the lubricant compartment is completely filled, follow this procedure:

1. Remove the guard from over the track adjusting mechanism.

2. With relief valve (1) opened one turn counterclockwise, force grease through fill valve (3) with a grease gun.

3. When the grease coming out of vent hole (2) from the opened relief valve (1) no longer has air bubbles, close the relief valve and continue filling until the track has 11/2 to 2 in. (38 to 55 mm) sag.

4. Operate the machine backward and forward to make the adjustment equal. Check the adjustment again.

TRACK ADJUSTMENT CROSS SECTION
1. Relief valve. 2. Vent hole. 3. Fill valve.

NOTE: Tighten valves (1) and (3) to 20 to 30 lb.ft. (2.8 to 4.1 mkg).

5. Make following track adjustments by putting grease into fill valve (3) with a grease gun until the track has the correct amount of sag.

6. Operate the machine backward and forward to make the adjustment equal. Check the adjustment again.

TRACK ADJUSTMENT
1. Relief valve. 3. Fill valve. B. Maximum permissible distance between rear of yoke and front of cylinder flange.