Does the 2500HD really have a different Rear Axle than the 3500 these days? When I bought my 3500 back in 2001 the dealer and I investigated and found that both trucks used the same axle and it was really the springs/wheels/tires that lowered the GVWR of the 2500HD. According to the current GMC site the 3500 now has a 9200 Rear Axle capacity and the 2500 HD has a 6900 Rear Axle capacity.

Again, back in 2001 they were the identical axle?

Springs/Wheels and Tires are easy to change for a higher capacity 2500HD, Axle is not. 3500 is not an option for me since GM doesn't make a 3500 Short Bed.