Front end wobble during braking on steep grades

[jordandvm]

We recently finished a 30 day RT from Oregon to Kansas and back, crossing over the Rockies both directions while the weather was good. While going down the steep grades of Vail and Monarch Passes, I experienced a severe wobble in the front end that shaked the whole tow vehicle when braking to slow down. This occured even when I’m downshifted into 3rd gear (automatic transmission). I try to keep my speed below 60 mph while descending steep grades. This is not the first time this has happened. It also occurred on other steep grades on other trips. But it doesn’t happen consistently on all grades.

Before leaving on the trip, I adjusted my Prodigy Voyager brake controller according to the manual instructions to see if it would negate the problem. It apparently didn’t help. I also rotated all the tires and rebalanced them before leaving. I don’t think I have any front end alignment problems, because it only happens on steep grades.
I’ve been concerned about the Prodigy Voyager being the right brake controller for my current 28’ CCD. I’ve been reasonably happy with it’s performance on trips. It was the original brake controller when we started with our 22’ CCD. I‘m thinking about upgrading to the Prodigy P3 controller. I don’t know whether this will make any difference in the wobble during steep descents, but I think I’ll have more peace of mind in ease of adjustment to get the right setting for the 28’.

Any thoughts on what’s causing the front end wobble? Has anyone else experienced this with their TV on steep descents?

Should I consider upgrading my brake controller?

Thanks