446B Backhoe Loader Transmission (Autoshift) Machine Preparation for Troubleshooting Caterpillar

Machine Preparation for Troubleshooting

Make reference to the following warning and pressure tap locations for all checks and tests of the transmission hydraulic system. If the problem area is not known, you should do the tests in the order that is given. For all tests, the oil must be at normal temperature of operation.

------ WARNING! ------

Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine. To prevent possible injury, perform the procedure that follows before the test is done.


  1. Move the machine to a smooth horizontal location. Move away from working machines and personnel.

  1. Put the speed/direction control lever in the NEUTRAL position.

  1. Activate the neutral lockout switch. Stop the engine.

  1. Permit only one operator on the machine. You should keep all personnel away from the machine or you should keep all personnel in the view of the operator.

  1. Activate the parking brakes.

  1. Lower the buckets (loader and backhoe) to the ground. Lower the stabilizers to the ground.

  1. Make sure that all hydraulic pressure is released before any component is adjusted in any way.

Troubleshooting can be difficult. A list of possible problems and corrections is on the pages that follow.

This list of problems and corrections will only give an indication of the type of problem and the repairs that are needed. Normally, more repair work or other repair work is needed beyond the recommendations on the list. This list cannot give all possible problems and corrections. The serviceman must find the problem and the source of the problem. The serviceman must then make the necessary repairs.

You should make a visual check first. Check the operation of the machine and then check with instruments.