GAWR is the number you MUST Stay under to prevent damage to axle and drive line components.

GVWR is the finalized number that the OEM manufacturer chose based on several different criteria (Though the factory original tire size has been noted as a recurring on several years of Ford Model Truck), this number can be exceeded within reason, most times without really noticing any major change in handling other than perhaps accelerated wear and tear. 

Then there's those of us that have kinda just gone off the deep end.  For example, my GVWR is 8500, I weight closer to 10,000. 

I'm currently in the process of doing an axle swap on my truck since the only major difference between a 92 W250 and W350 was the leaf spring pack (Which you got on the rear with the Heavy Duty package on the 3/4 ton gasser) and the axles used. 

Dodge used a fiberglass little fender extension that attached to the edge of the bed's wheel well to extend out over the second tire, so converting it is actually rather easy. 

I've already obtained a Spicer 70 Dually axle for the swap and a set of appropriate dually rims for the period, just need to get the fenders and add the running lights once I start the swap.

You can see the fender style I'm talking about here:

Hello all! I've recently become interested in truck campers , and have been reading this forum for a couple of weeks gathering info. I would like to know if there.is any problem using a TC on a GMC Sierra 2500 (denali) with a sliding sunroof????  Any one have experience with this?

I'm just wondering if the cab over portion of a TC puts ever puts any stress on this area.

Thanks