paul bell

Hello I'm new here! But I've been in various forums for years including LS1tech where I'm a moderator.

I'm watching the market for a 2003 and up 3500 van. It can be a work beater as that's what I'll use it for.

I want the 6.0 engine.

The only thing I can't determine is the rear end. I want the full float rear with bolt in axles and 10-1/2 inch ring gear.

Did all 3500 vans come with the full float/10-1/2" rear?

Thanks!

mountainmanjoe

yes
https://en.wikipedia.org/wiki/10.5%2...t_Differential

If you remove the wheel cover, you will see the axle protruding through the wheel.

paul bell

Thank you sir.

There's two ways to externally determine which rear it is-if I had access to the truck.

What combination of other options would result in a van with the full float/10-1/2" rear?

Triaged

The 14-bolt full floater 10.5" is not in all. I know my 2015 3500 came with a semi-float 9.5" 14-bolt open diff. Did some years come with a Dana 70? I'd have to look it up

At any rate, check the RPO codes. The different axles tend to have slightly different gear ratios. For example "GU6 AXLE,REAR,3.42 RATIO" on mine is 9.5". I think most of the 10.5 I have seen are (at least close to 2015) are "3.54 ratio, opt GH0". This might not be a hard rule but might still help when searching.

mountainmanjoe

If the goal is to haul work cargo, then isn't the bottom line just the cargo capacity printed on the door sticker?
Full floating axles are expensive to maintain.

paul bell

Thanks folks.

I'll look into finding out if the ratios are different between the 9-1/2" and the 10-1/2" rears.

William Kisselstein

Vans tend to get the next step down, I can't remember seeing one with the full floater. Doesn't mean it didn't or couldn't happen, it's a bolt-in, but I don't remember seeing it and I've looked at a lot of vans.

G3500 Toy Hauler

FYI - My 2001 Cutaway (cab and chassis) came with a 14-bolt full floating rearend. My guess is that one does not have to limit their search to the van and they could look into the Cutway model as well. At least both have the arched frame over the rear axle - unlike the trucks.

Joe, Do you think that kind of rearend you posted above might work on my Cutaway? (Should I find out that changing the ratio is the way for me to go.)

mountainmanjoe

You mean the image? That was a random image I found on the internet to illustrate what a floating hub would look like.
At first glance, it looks like the offset is wrong and the driveshaft won't clear the fuel tank, but I'm no expert and I've owned neither cutaways or floating axles.
If you go to gmupfitter.com there are detailed technical drawings of van chassis with all relevant dimensions.

G3500 Toy Hauler

Thanks.

Unlike Trucks - aren't all VAN fuel tanks in the back? (Unless it has dual tanks.)