1997/09/15 Caterpillar

TH62 (3LN, 4TM) TH63 (3NN, 5WM) TH82 (3JN, 3KN) TH83 (3RN) Telehandler

Reference: SENR5839, Pages 14 And 15, SENR5847-01, Page 5.

Chart 1. Transmission Clutch Sequences.

NOTE 1: Within Columns (2) and (3) in Chart 1:

· means the unit is energized or engaged.

o means the unit is de-energized or disengaged.

NOTE 2: In Chart 1, Clutch (E) is always engaged unless the pressure is bled off when another clutch is engaged.

Illustration 1. Transmission Solenoid Connections.

The following is an explanation of the clutch and solenoid operation. Please refer to Chart 1. Column (1) is the shift speed and direction selected on the Transmission Control. Column (2) shows the solenoids engaged for a specific transmission selection. Column (3) show the clutch or clutches engaged for a transmission selection.

The Solenoid Assembly-Cartridges listed in column (2) of Chart 1 are refered to as the Transmission Control Manifold in SENR5839, Page 15. The 8I-4586 Solenoid Assembly-Cartridges are part of 8I-4563 Valve Group-Control.

The Solenoid Assembly-Cartridge will be refered to as Solenoid Assembly in the following information. Illustration 1 shows the position of each Solenoid Assembly. They are identified below.

(A) - Reverse Solenoid Assembly.

(B) - Second Speed Solenoid Assembly.

(C) - First Speed Solenoid Assembly.

(E) - Forward Solenoid Assembly.

(F) - Speed-Split Solenoid Assembly.

Column 1, Shift Speed and Direction:

A - First Speed Forward. Solenoid Assembly E is energized which engages Clutch A. Solenoid Assembly B is energized which engages Clutch D and disengages Clutch E. Solenoid Assembly C is energized which engages Clutch C and disengages Clutch D.

B - Second Speed Forward. Solenoid Assembly E is energized which engages Clutch A. Solenoid Assembly B is energized which engages Clutch D and disengages Clutch E.

C - Third Speed Forward. Solenoid Assembly E is energized which engages Clutch A. Clutch E is also engaged. Refer to Chart 1, NOTE 2.

D - Fourth Speed Forward. Solenoid Assembly E is energized which disengages Clutch A. Solenoid Assembly F is energized which engages Clutch F. Clutch E is also engaged. Refer to Chart 1, NOTE 2.

E - Neutral. Clutch E is engaged.

F - First Speed Reverse. Solenoid Assembly A is energized which engages Clutch B. Solenoid Assembly B is energized which engages Clutch D and disengages Clutch E. Solenoid Assembly C is energized which engages Clutch C and disengages Clutch D.

G - Second Speed Reverse. Solenoid Assembly A is energized which engages Clutch B. Solenoid Assembly B is energized which engages Clutch D and disengages Clutch E.

H - Third Speed Reverse. Solenoid Assembly A is energized which engages Clutch B. Clutch E is also engaged. Refer to Chart 1, NOTE 2.

TROUBLESHOOTING

Illustration 2. Troubleshooting Schematic.

Use Charts 1 and 2 and Illustrations 1 and 2 for troubleshooting.

NOTE: The transmission fluid must be at operating temperature of 83-93 degrees C (180-200F) to obtain correct fluid level and pressure readings.

Prior to making any pressure checks, verify that both the Parking Brake and Override Switches are functioning properly.

Always use the Parking Brake and block the wheels when making pressure checks.

The Transmission Neutralizer (Override) Switch on the dash must be in the off position.

The Transmission Isolator (Parking Brake) Switch on the Park Brake must be disabled.