A road we take many times is from Flagstaff, AZ to Phoenix. Flag is close to 7k, Phoenix about 1K. At the beginning, I slow down enough to get into 5th, but don't lock it, then hit the retarder on and off during during the drop. Very seldom, do I have to hit the mains, unless you are in front of me and have geared-down too much. If there is a secret, as soon as one sees the "warning, steep 6/7% grades ahead", get the coach into 4th or 5th, toggle the retarder, and as the Eagles say, "Take It Easy". ^.^d If you come blowing by me, no problem, but I'll pass you on the hills, and I'll watch your brake lights being on all the time on the next drop.
Coming back from the Sierra's the grade coming down to Bishop from the Mammoth cutoff is 6% don't know for how far though. 4th gear first click on the retarder holds 50 MPH no brakes, trans never got above 210 deg. My brothers 2005 Monaco with exhaust brake needed to be in 3 gear to hold him to 35 to not have to ride the brakes. He saw my brake lights and thought I was riding them. Let him know retarder on our coach lights up the brake lights.
Ours do not light up, have checked, and I like it! I have a hunch that the newer SOBs light up, not only the coach, but the toad, as well. ::)
Yep, the boat trailer lights were lit up as well. I have seen the posts on how to eliminate the brake light from coming on with the retarder, but it's the glass half full or half empty issue. My preference is to leave it as it is even though the argument is "what if you slam on the brakes"? my take is if they don't see any brake lights on they might not know I am going slower than they are. To each his own though.