DIFFERENTIAL AND BEVEL GEAR GROUP 7D2830 - Caterpillar

Problem: Transmission does not operate in FIRST speed FORWARD or REVERSE.
Probable Cause:
1. FIRST SPEED clutch (K1) not engaged (slips) because of: a. Low oil pressure.b. Discs and plates have too much wear.c. Broken components.PROBLEM: Transmission does not operate in SECOND speed FORWARD or REVERSE.
Probable Cause:
1. SECOND SPEED clutch (K2) not engaged (slips) because of: a. Low oil pressure.b. Discs and plates have too much wear.c. Broken components.2. See, TROUBLESHOOTING ELECTRIC CONTROLSPROBLEM: Transmission does not operate in THIRD speed FORWARD or REVERSE.
Probable Cause:
1. THIRD SPEED clutch (K3) not engaged (slips) because of: a. Low oil pressure.b. Discs and plates have too much wear.c. Broken components.2. See, TROUBLESHOOTING ELECTRIC CONTROLS.PROBLEM: High control pressure at pressure tap.
Probable Cause:
1. Operation of main relief valve not correct.PROBLEM: Low control pressure at pressure tap.
Probable Cause:
1. Operation of main relief valve not correct.PROBLEM: Pump noise not normal.
Probable Cause:
1. Loud sounds at short intervals that give an indication that particles are going through the pump is caused by pump cavitation.2. A constant loud noise is an indication of pump failure.3. Air at the inlet side of the pump (aeration).PROBLEM: Back-up alarm does not sound when selection lever is put in REVERSE.
Probable Cause:
1. Failure of back-up alarm switch.2. Failure of back-up alarm.3. Failure in the wiring of back-up alarm circuit.Torque Converter
PROBLEM: Torque converter gets hot.
Probable Cause:
1. Low oil level.2. Low water level in engine radiator.3. Restrictions in oil cooler or oil lines.4. Too much operation of machine at or near stall speed (overload).5. Too much oil in the converter housing around the converter because of: a. Too much oil leakage inside the converter.6. Not enough oil to the converter because of: a. Oil pump failure.b. Too much leakage in transmission.Troubleshooting Electric Controls
ELECTRONIC SHIFT CONSOLEWhen a DIRECTION and SPEED SELECTOR is moved to a direction and speed, normally the transmission will engage the correct direction clutch and speed clutch. When it does not, there is a problem which can be in the four solenoids, the wiring harnesses and connectors, or the direction and speed control unit on the steering column.When there is a problem, check the operation of the solenoids first.M-1 Solenoid
Should the M-1 solenoid fail to energize (open), the problem (failure) would show up only when the operator tries to operate the machine in reverse.M-2 Solenoid
Should the M-2 solenoid fail to energize (open), it would show up only in FIRST SPEED (FORWARD or REVERSE). Failure of the M-2 solenoid to energize would cause the third (K3) speed clutch to engage instead of the first (K1) speed clutch. The machine would go forward or in reverse, but would not have as much power in third speed as it would in first speed.M-3 Solenoid
Should the M-3 solenoid fail to energize (open), the FORWARD or REVERSE direction clutches would not engage and the machine would not move.M-4 Solenoid
Should the M-4 solenoid fail to energize (open), the transmission would operate in THIRD SPEED (FORWARD or REVERSE) only, regardless of what speed position the direction and speed selector is moved to (except