[4Doors]

I had a question asked of me how the grade braking feature of the Allison and surge brakes on trailer worked together. All of the trailers I have pulled have had electric brakes. My thought is that in "normal" mode, there would not be any problems. In "T/H", 5-4 shift would not cause any problems, 4-3 most likely very few (disc brakes on trailer may set), and 3-2 could lock up disc but not drum. I can see where if the trailer brakes did lock up, they would also release themselves because the trailer would then "stop" and release the brakes. Would/could this cause some sort of "surging" effect? Most of the times I've experienced these kick downs, I should probably been driving slower in the first place. Anyone with real "first hand experience?

 

[DalDMax]

I have a small tandem axle trailer with surge brakes on both axles. When the trailer is loaded and I'm running T/H mode (I always run T/H when towing due to da Juice) that the surge brakes will activate due to the truck slowing down. Feels like someone behind the truck pushing, then pulling, then pushing and so on. I don't have the problem when using the brakes.

 

[4Doors]

I figured out my own answer after thinking about it this weekend. The master cylinder on the brake does not care how the pressure is applied. It can be by the trans. or it can be applied by the brake peddle of the truck. All it is doing is sensing the actions of the truck.