Looking to buy a Chevy Express or GMC and I want to use it to tow about a 7,000 lb boat. I have read that the rear axles are different, not sure if that is true or not. I have read that the 3500 uses a full floating axle and the 2500 uses a semi float axle. I'm guessing the 2500 would probably suit my needs but I'm leaning towards a 3500 just to be safe and sure. I'm looking at the 6.0 somewhere in the 2012 to 2017 range, maybe a bit newer. Any thoughts and comments are greatly appreciated

 

I found this site useful when deciding on my 2011 1500. https://towingcap.com/

From what I remember the 2500 and 3500 had the same 10,000 pound towing capacity with the 6.0. The difference was in the payload capacity and it wasn't a huge difference. I think the 3500 might ride more rough without weight in the back.

 

Not sure when it changed but my 2015, 3500 passenger has a 9.5" semi-floater.

 

agreed. The 2500 and 3500 currently use exactly the same rear axle. The only difference is the springs.

 

I am trying to piece together a better understanding the axle situation on these vans.

All varieties of the van these days come with the 9.5" semi float axle. They have the 3.42 ratio (RPO code GU6). The 3500 vans have a trailer limit of 10,000lbs (and tongue weight limit of 1,000) but the combined rating is only 16,000lbs - so unless you're a skinny dude and have an empty, stripped down cargo van with even the passenger seat removed, you're going to have a hard time getting the full 10,000lbs trailer without exceeding the 16,000lb combined weight.

However, the duramax V8 vans, back when they were available, up until 2016 or so, had a 10.5" 14 bolt full float axle that is an absolute beast, legendary for being tough. In addition to the larger ring gear, it has a straddle mounted pinion which is much stronger. These are the axles with the 3.54 ratio (RPO code GH0). These vans still had the 10,000lb towing limit, which at this point I presume is because of the frame - but the combined rating was from 17,000lbs (for passenger vans and short wheelbase cargo vans) up to 18,500lbs (for the extended cargo van only.) Presumably this extra rating over today's 3500s is because of the axle. I'm not sure why the extended cargo van is rated for an extra 1,500lbs over the standard, but my best guess is the springs. That 18,500lb rating would allow you to tow the full 10,000lbs with an almost fully loaded van (up to 9500lb including 1000lb on the trailer tongue.)

Earlier versions of the 3500 vans apparently had a 10" Dana Super 60 full float axle. I don't know much about this - I don't know what years this configuration was available, nor do I know if it was gas, duramax, or both. I also haven't researched what the weight ratings are. The Dana is a tough axle but not quite as tough as the 10.5 (no straddle pinion).

The 10.5" full float axles are available and would be a pretty simple swap for my 2016 3500. It's just not cheap, $2500 for the part.

My van has a GVWR of 9600lbs. I tow a camper that is up to 7800lbs fully loaded. That means my van can weigh up to 8,200lb before hooking up the trailer, add 1,000lb tongue weight and that lmakes for 9,200 for the van, so I can tow a fully loaded trailer and still load up to just 400lbs shy of the van's GVWR.

For your particular situation with a 7000lb boat, you could go either way, but the 3500 will leave you with more capacity to load more stuff in the van. If you don't tend to drive around loaded I don't think it would matter much.