666 TRACTOR SCRAPER Controls Caterpillar

1.1. Tractor Individual Wheel Brakes
2.1. Differential Lock
3.1. Hydraulic Retarders
4.1. Bowl
5.1. Apron
6.1. Ejector
7.1. Transmission Hold
8.1. Traction Unit
9.1. Bowl - Apron

Tractor Individual Wheel Brakes

Push handle forward to apply tractor right wheel brake.

Pull handle back to apply tractor left wheel brake.


Do not use tractor individual wheel brakes to steer tractor.

Differential Lock

Depress pedal to lock differential.

Release pedal to unlock differential.


Do not attempt to turn tractor when differential lock is applied.

Hydraulic Retarders

Pull lever back to apply retarders.

Push lever forward to release retarders.

Anticipate the use of the hydraulic retarder. Three or four seconds are needed to engage the retarder once the lever is moved. Handle position determines the amount of retarding. The farther back the handle, the more the braking action. Use the retarders at least once a week to keep seals lubricated.



(2) HOLD





(2) HOLD


(4) FLOAT - Control will lock in this position until moved manually.



(2) HOLD


(4) LOCKOUT - Control will lock in this position until ejector returns to rear or another control is engaged.


Do not move ejector forward when bowl is full and apron is closed.

Transmission Hold

Depress pedal to lock transmission in desired gear speed.

Release pedal to allow transmission to shift automatically.


Do not downshift when transmission hold pedal is depressed.

Traction Unit

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

Operating with traction unit fully engaged under certain conditions, such as uphill, may reduce weight on front wheels below safe steering level. Always operate traction control with caution to maintain safe steering control. Do not engage traction unit when traveling above second transmission range.


Turn traction control knob to left (counterclockwise) for normal operation. Turn knob to right (clockwise) for transferring additional weight to the drive wheels to increase traction. The more the knob is turned to the right the greater the weight transfer.

Bowl - Apron

Push handle forward to lower apron.

Handle in upright position is HOLD.

Operation of standard apron and bowl controls is the same. (See page 13.)