How to do a tug test in an automatic allison transmission.

Tug test.

Words matter.

Pretrip brake check? Very different story.

 

explain the tug test one more time

 

oh ok. well go luck pumping the brakes with the brakes set. dont forget to leave the key off

 

TruckerHart, I don't know why you are catching grief over this. The DMV exam includes a section for testing the airbrakes and one of the tests is to set the tractor parking brake, release the trailer parking brake and then put into gear and try to move forward. The tractor parking brake should prevent that if it is functioning properly. Then do the same for the trailer parking brake.

The Oregon DMV manual says if your vehicle design does not have a part or system to be tested then to skip that section in the test. I would check your DMV web site for a FAQ section that might answer this, or call the DMV and ask them how to handle the situation. You might also check the operators manual for your truck, (usually online version on their website) and it should describe how to inspect your parking brake function. I know on the CAT haul truck I drove with an auto trans, there were a couple of buttons on the sides of the shifter to limit its upshifting range and to manually shift it up or down. By holding both buttons in while you move the shifter to DRIVE, the parking brake would remain engaged and you could perform the parking brake test that way.

BTW, our CAT haul trucks used a 7 speed Allison transmission.

 

The tug test that is discussed here falls under the topic " Properly Hooking up a Trailer".
It has nothing to do with the brake check.

I hope you did some hooking/unhooking in driving school.

 

Wrong. The OP clarified he used the wrong terminology and what he meant was the pretrip parking brake test. It would be a shame for him to skip that test if the manufacturer has a known bypass method specifically for testing the parking brake which the DMV examiner likely knows about since they test thousands of students.

This being a trucking school thread, no DMV exam requires dropping and hooking. So a tug test would never be done for the exam.