Additional Information for Troubleshooting Transmission, Differential Lock, and All Wheel Drive Solenoid Failures on Backhoe Loaders{3030, 3258} Caterpillar

Backhoe Loader:

416 Series E (S/N: LMS1-UP)

416F (S/N: KSF1-UP; LWT1-UP)

420 Series E (S/N: DJL1-UP; DAN1-UP)

420F (S/N: LKH1-UP; JWJ1-UP; SKR1-UP)

422E (S/N: MAW1-UP)

422F (S/N: LRH1-UP)

428E (S/N: DPH1-UP)

428F (S/N: LBH1-UP; SJW1-UP)

430 Series E (S/N: MXB1-UP; SWC1-UP)

430F (S/N: RDF1-UP; RGS1-UP; LDY1-UP)

432E (S/N: JBA1-UP)

432F (S/N: SEJ1-UP; LNR1-UP)

434E (S/N: SEF1-UP; SJL1-UP)

434F (S/N: LDH1-UP)

442E (S/N: EME1-UP)

444E (S/N: NBA1-UP)

444F (S/N: LJJ1-UP)

Introduction

Certain Backhoe Loader may suffer premature solenoid valve failure due to fine contaminates between the valve body and hydraulic piston.

The following conditions may occur:

• Differential lock staying activated when the button is released.

• Transmission selecting two gears at one time and locking up.

• Transmission not selecting some gears.

• All Wheel Drive not activating when selecting.

• All Wheel Drive staying engaged when turned off.

• Differential lock not activating when selected.

Cause

Contamination control of transmission at manufacturer. Small black ferrous debris from case getting stuck in solenoid valves jamming the valve and stopping the valve from opening / closing when commanded.

Resolution

Note: Refer to table 1 at the end of this document.

1. Confirm that a problem exists.

2. Activate the affected function.

   1. Test for electrical supply to the solenoid.

   2. Test hydraulic pressure at the test port for the function affected.

      Note: If an electrical supply is present at the solenoid, but no oil pressure at the test port, the solenoid may be faulty.

3. Deactivate the affected function.

   1. Check for electrical supply to solenoid, the electrical supply is off

   2. Check for pressure at test port, none is observed.

      Note: The solenoid has no electrical supply but pressure is still present, the solenoid may need replaced.

Transmission Solenoid

The following procedure must be performed before replacing the transmission solenoid.

1. Move the machine to a smooth level surface away from other operating machines.

2. Place the transmission "FORWARD/REVERSE" lever in the NEUTRAL position.

3. Activate the neutralizer switch on the front console. Refer to the Operator Maintenance Manual (OMM) for location of the switch.

4. Activate the parking brake.

5. Ground all implements including the loader, backhoe, and stabilizers.

1. Perform all steps in the section titled Transmission Oil and Filter- Change in the OMM for the machine being repaired.

2. Inspect and clean the drain plug and screen for debris.

3. Replace the affected solenoid only after the transmission oil and transmission filter have been changed.

4. Engage each valve 10 times to insure proper function. Valves will be engaged in order listed in table 1.