I got a set at Tulare. They are made from extruded aluminum and are extremely strong, in addition to being functional. Since they are finned aluminum, they should help cool the lube. Using two of them adds about 2 quarts of lube capacity to the trans. That is an extra 50% in the NV4500!
At Tulare, Verlyn had one side of his dually sitting on a pair of coolers, one under the front tire and one under a rear tire. They were on their side, the weakest direction for supporting weight, and showed no sign of fatigue.