IDLER A.-FRONT 1B0306 - Caterpillar

Introduction
A 146-6820 Circuit Board Kit is now available for repairing the following transmission control groups: 109-3596, 109-3597, 109-3598, and 109-3599 Non-Autoshift Controls and 109-3664 and 109-3665 Autoshift Controls.The new kit includes a circuit board, springs, contact wipers, O-rings, grease, and screws to install the new circuit board. The new circuit board is now manufactured with a silver-graphite material on the contact points. This material should double the life of the contact points, thus greatly increasing the life of the transmission control.If the transmission controller has damage other than a worn circuit board, the control must be discarded and replaced with a new one.Do not perform any procedure outlined in this publication or order any parts until you have read and understood the information contained within this Special Instruction.Model And Serial Number Effectivity
Transmission Control Group.Installation Procedure
146-6820 Circuit Board Kit.
(1) Circuit board. (2) O-rings. (3) Grease. (4) Contact wipers. (5) Screws. (6) Springs.The procedure outlined in this Special Instruction is used to replace the upper housing circuit board. The controller shown in the procedure is a 109-3596 Transmission Control Group, however the circuit board replacement procedure is the same for all the transmission controls listed in this Special Instruction.1. Before disconnecting any wiring harnesses or removing any parts, follow all safety precautions for the particular machine being serviced.
Remove Transmission Control Group From Steering Column.2. Remove the transmission control group from the steering column (use the instructions provided in the Service Manual, if necessary).
Remove Lock Cover.
(1) Cover. (2) Socket head capscrews.3. Remove lock cover (1) by removing four Allen head cap screws (2) from the side of the cover.
Separate Top And Bottom Housings.
(3) Phillips head screws. (4) Top housing. (5) Bottom housing.4. Remove four Phillips head screws (3) securing top housing (4) to bottom housing (5).
Do not pull the two housing halves too far apart before disconnecting the wiring socket or damage to the transmission control can result.
Disconnect Two Circuit Board Connections.
(6) Fixed row of pins. (7) Wiring socket.5. Carefully separate the top and bottom housings. There are two connections (6) and (7) between the circuit board in the top housing and the circuit board in the bottom housing. a. As the housings are separated, the fixed row of pins (6) attached to the bottom housing circuit board will pull out of the socket in the upper circuit board.b. Disconnect wiring socket (7) coming through the top housing circuit board and attached to the bottom circuit board.c. The two halves of the housing should now be separated.6. Remove the O-ring and discard.7. Carefully check the bottom housing and wiring harness for damage. Replace the control if this damage could cause the control to malfunction. Repair of the control is not possible.8. If the bottom housing is not damaged, clean the circuit board and set the housing aside. The bottom housing circuit board does not need to be removed.
Remove Five Screws (8) From Circuit Board.9. Remove five Phillips head screws (8) holding the circuit board into the housing and discard.10. Pull the