Can I make my 2500 a 3500?

[Ozzie]

I'm curious...

An RV forum I frequent has ongoing discussions about the carrying capacity of the 2500 vs. 3500 models. The weights are quite different yet the only hardware differences seem to be in the springs. This has been a hotly contested topic that draws fire from the 'weight police' as many 5th wheel units are over for the 2500's.

I have airbags right now, but understand these don't legally add to the carrying capacity even though they do...:boggled:

How hard would it be to change the rear springs to the equivalence of the 3500? I can get my truck recertified to reflect the change?

I'm curious to see how our boys here weigh in on this...(sorry for the pun):bigear:

 

[Ozzie]

I should also add that I researched this last year when I was doing my new tires...and found that my stock rims would be the weak point in load capacity if I were to change my springs to the 3500's...the new tires have increased load capacity.

 

[Unit453]

I dont think its the springs. I think the only major difference is the fact that 1 tons have an extra leaf spring, which is why you cant get a 3500 in a short box. Everything else is identical. Otherwise, there are subtle differences like tires and rims. I believe their wheels are a 16x7 vs a 16x6.5.

Add a leaf spring and you got a 1 ton.

 

[Ozzie]

I really am bummed that GM didn't offer the 3500 with the short box...that is what I would've bought in the first place.
Ford makes it, but I'm a Chevy guy.

Don't we have some vendors here that provide suspension parts?
My understanding of this recertification process is that shops that modify suspension parts can put in for this sort of thing.
I'd like to know the process and parts needed for my truck.

I do realize that RVers are not held to the same weight standards as commercial drivers, but that all could change.
My current RV trailer is a bumper pull, so there isn't an immediate need from my part, but should I change to a 5'er...3500 here we come.

 

[Unit453]

Nor-Cal Nick should carry most of those parts I would imagine. In fact, adding a leaf has been very popular in the past to upgrade the load carrying capability of the truck.

 

[Ozzie]

Thanks Nick - I may ask him for his input on weight recertification then...this one is a little hard to research and he may have gotten into this before.
I have found add a leaf kits at a reasonable price, but they won't tell you the additional carrying capacity of their product.
This must be a sensitive area as documentation is really hard to find.

 

[GMCYA]

You have to be talking about rvdotnet :rolleyes5:


A few extra springs, one number on the door decal, and a lil rougher ride that a set of surlastic shackles will take care of and you have your self a one ton. .

 

[trouttrooper]

Here's what I know as fact that pertains to what you are dealing with.

1. 3500 SRW has 1 more spring in the spring pack with some having an overload spring on top of the pack (however it's 9,900 GVWR either way). At any rate it's 700 lbs more than 2500HD.

2. 3500 SRW comes with 16x7 rims vs 16x6.5 rims. Although my spare is a 16x6.5 rim, even listed that way on the door.

3. 3500 SRW come with 265/75 R16 E (3,415 lbs) 2500HD come with 245/75 R16 E (3,042 lbs). Big difference there.....

Everything else mechanical/physical is the same between the two when comparing the same engine/tranny combo's.

Something I've heard as a rumor is the 3500 has another cross member or something under the bed for strength. I've never looked and compared but I kinda doubt there's a difference.

 

[Ozzie]

Now we're getting somewhere...thanks for that.
700 pounds isn't a lot, but it could maker the difference between being legal or not. I have found the helper springs (add a leaf), but they won't give any ratings...I'm hoping someone that sells them can chime in.

The tires I knew about and have already gotten bigger tires with a much higher payload. The rims are something I am drawing a bead on (oh no - not another pun)...I'll need some 7 inch rims for my 16 inch tires with the higher weight capabilities.
Nick has been after me to get some black rims for my truck - so there is the justification for that...:thumbsup:

 

[83GMCK2500]

In a recent thread (this forum) about 3500 SRW Overloads I posted pics of each leaf spring configuration. Those pics were taken directly from a GM Electronic Parts Catalog.

Lemme see if I can find a frame & crossmember picture.

 

[FastCR]

I keep getting shot down on this one but I coulda sworn awhile back on the other site someone showed that the chassis is slightly different.

 

[Unit453]

It isnt. Its exactly the same. Like everyone has said, its pretty much the exact same truck, minus a set of leafs.

Trooper nailed it on the head with everything. Thats why I love this site, because its full of knowledgeable people. :thumbsup:

 

[ak diesel driver]

I was always under the impression that the one tons had slightly more brakes.

 

[trouttrooper]

not since the '99 body style came out. 2500LD has smaller brakes, but the 2500HD is the same. It's essentially a 1 ton badged as a 3/4 ton.

 

[83GMCK2500]

Ohhh, RPO goodness:

JH6 - BRAKE HYD POWER, 4WHL DISC, 9,900 LBS BRK HYD PWR DISC
JH7 - BRAKE HYD POWER, 4WHL DISC, 12,000 LBS BRK HYD PWR DISC

So now all we need are various members with different truck configurations to post up their RPOs, I'll go look at mine.

EDIT: My truck is a JH6 truck.

 

[Ozzie]

Wow - there ARE differences in the brakes?
I was hoping our membership would get into these differences...I'll bet you guys are more capable of getting this figured out than those RV forums where everything thinks they have all the answers. Nice work :thumbsup:

 

[83GMCK2500]

Just throwing out a hypothesis here, it's going to take some digging but what if the caliper pistons are different diameter?

--JH7 Brakes--
18046142 - Caliper, Left
18046143 - Caliper, Right
18044321 - Caliper Piston (AC Delco #179-1350)
19133307 - Pad Kit (AC Delco #171-690)

--JH6 Brakes--
18040100 - Caliper, Right
18040101 - Caliper, Left
18040104 - Caliper Piston (AC Delco #179-1338)
18048101 - Pad Kit (AC Delco #171-670)

So obviously I dug around, those are GM part numbers followed by a shortened description. Now if we could get the specs on the pistons, we'd know if they're different diameters, something that would effect braking capacity.

 

[Unit453]

I think the differences were between the 2500 LD trucks and the 2500 HD's. Light Duties were also known as heavy duty half tons. Between the two, there were differences but you're asking about the current generation 3/4 and 1 tons.

 

[Ed HD]

Ours is also a JH6 truck. 2500HD.

 

[RayMich]

Here is some information I got from GM a while back.

It is my understanding that the brakes and suspension on the GMT800 (Old Body style) and the GMT900 (New Body Style) are the same.

According to this chart, the 2500HD and the 3500SRW have the same brakes. The dually has different rear brakes. I suspect that the difference in part numbers in the above post is due to different brake proportioning due to load distributions.