I think I'm gonna do a DRW axle swap, add flares, and dually wheels (along with whatever else needs to take place) and convert mine to a dually.. My first question is: Are there rear springpack differences between the 2500 and 3500? I was looking at my buddy's 95 3500, and the rear packs look identical..

ther sure seemed to be alot of differant spring counts in that thread. mine are like the last post.1 short flat spring3 arched springsa spacer 1 overload

mine...

I see how it would. What I don't understand is the class-rating of 2500 vs 3500 (3/4ton vs 1ton) if they have the same spring rating.

i am looking at the charts in the owners manual that came with my truck and it says; QC4X4 2500 w/3.55 or 4.10 rear gear and 5 or 6 speed GCWR 20k 3500 w/3.55 rear gear 5 or 6 speed GCWR 20k 3500 w/4.10 rear gear 6 speed GCWR 21.5k GVWR 2500 8.8k 3500 11k ther appears to be a little more differance than i remembered. the 3500 has a good bit more payload than the 2500, but not alot of differance in the combined load unless you have the 4.10 rear end and HO engine and 6 speed. if my memeory serves the HO was the only way to get the 6 speed.

IIRC the HO only got the D80, alnog with the 6 speeds? I thought somewhere the D70 is rated for 10K axle rating. Granted on a 2500 you run out of tire first. Unless ur running 19.5s. My 265/75/16 are only rated up to 3400ish as singles. Hence my rear weight rating of 6800ish. The Duallys with the D80 are obviously more. Not sure what a D80 is rated at. I have gone to about 7300 on the rear at one time. Truck squated, tires to full psi and I took it easy. Tires got warm but no issues. It was nice to really work the Cummins that time.

mine has the D80. i dont know what it is rated for either. i also run 265/75/16's rated just over 3400. i have hauled 2 cubes of brick in mine before at about 3k each. one in the front of the bed theother over the axle. it went to the overloads and sat nice and level. the truck handled it fine. it was a 150 mile trip on the high way, no issues.

During my rear swap

the overloads on my 02 is one thicker single instead of a double.