Sx3 mike rubish

The basic operations and procedures for your SmithCo side dump trailer. Start here to learn the basics.

pre-check on your truck

Using the DOT checklist, ensure that your truck is properly checked prior to its operation. This includes greasing your 5th wheel to provide lubrication from truck to trailer to ensure smooth operation without sticking.

hooking up to the trailer

Once you are lined up, back up to the trailer. You will hear, and feel, the trailer connecting to the 5th wheel. Once you are connected, give the trailer a test pull to ensure it is securely locked into the 5th wheel. 

Once all is secure, now is a good time to raise your landing gear to ensure it is out of the way. 

connecting the lines from truck to trailer

Ensure all lines are hooked up to the trailer securely and in their proper place. 

  1. Hook up the airlines
    1. Red is Emergency Air
    2. Blue is Service Air
  2. 7-way cord to operate lights
  3. Tarp operation cord – if applicable
  4. 6-way cord for optional trailer functions
  5. Hydraulic hoses (pressure & return) for tub operation

testing the functions of the trailer

In the cab, test the function of your lights (brakes and signals), the tub dump/return and tarp operation. 

NOTE: To dump your tub, your tarp needs to be fully open if you have the Tarp Lockout system.

To test the Dump Cycle:

  1. Press in the clutch
  2. Engage PTO
  3. Release the clutch
  4. Now you can use the dump switch for dump and return*
  5. Check the operation of your tarp. Ensure it opens and closes all the way. 


*Trailers with hydraulic valve on the trailer must have air supplied to the trailer to test the tub dump/return.

trailer walk around

Before you start your haul, you should always ensure that all functions of the trailer are properly working. Check the following things:

  1. Ensure tub hinges are set to the correct dump side. If you need to switch dump side:
    1. Remove the pin from the hinge
    2. Hinge in = dump to that side
    3. Hinge out = dump to opposite side
  2. Check that the drain plug is secured in place.
    1. If the drain plug is not secured in the tub, you can find it inside the frame on the driver’s side.
  3. Air up the suspension – if applicable
  4. 3rd axle lift is set to operate from cab – if applicable
  5. Check operation of all lights and turn signals
  6. Check the condition of the tarp – if applicable


You are now ready to use your side dump.

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