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?