We have an 06 Rampage 387(40 foot 5er). When we first got it I took it to the factory in Hemet and had them put a 2 inch "lift" on it. This consisted of cutting the shackles off, welding a piece of two inch square tubing to the frame rail, the whole length of the triple axle. Then welding new shackles to the square tubing. Then they added cross braces for each axle, side to side. Also made out of 2inch square tubing. They said this was all the "newest" updates they had made to the triple axles at the time, whatever that means.
That was over two years ago with COUNTLESS number of trips and HEAVY loads, no problems yet, knock on wood, lol. Dry weight of trailer is 12,9xx.
Thanks for the heads up, could get kinda crazy out there if one of our trailers was to come apart...