# 1500HD front end question



## hairygary (Feb 19, 2009)

So i just purchased a 2002 1500HD as my daily driver and backup plow truck. I have done alot of research before buying the truck and I understand the differences.

small frame than 2500HD , but bigger frame than 1500 (non Hd)

smaller rear end than 2500 HD 6.0, but bigger rear end then 1500 (non HD)

I checked my rpo codes and it says it has rpo code 6GL and 7GL, which I believe to be the GL torsion bar, which is the same torsion bar as the 2500HD. 

Okay, so to my question, the boss plow selector says i can only but a 7-6 plow on it, but what exactly is different on the front end of it as opposed to the 2500HD, besides a smaller frame, that would prohibit me from putting a bigger plow on it and what is different about the front suspension. I have read on here that people put bigger plows on a 1500HD, but I want to know the difference is.


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## buckwheat_la (Oct 11, 2009)

i have a question for you, what is the difference between the rear end in the 1500hd and the 2500hd ? this is the first i have ever heard of this, as far as i have been told the only difference between the two is the frame, but i could be mistaken. as far as your question, track down B&B, he knows a lot about the chev power trains and frames


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## Newdude (Dec 4, 2006)

buckwheat_la;1030257 said:


> i have a question for you, what is the difference between the rear end in the 1500hd and the 2500hd ? this is the first i have ever heard of this, as far as i have been told the only difference between the two is the frame, but i could be mistaken. as far as your question, track down B&B, he knows a lot about the chev power trains and frames


2500:

GVWR 8600lbs

Only came with the 6.0 and 4L80E.

Lower payload, *semi-floating rear axle (9.5")*, tows less, frame is between a 1500 and 2500hd in strength (became 1500hd in a sense).

2500hd:

GVWR 9200lbs.

6.0 w/ 4L80E, 8.1 w/ Allison, 6.6 dmax w/ Allison.

Tows more, *full-floating rear axle (10.5" or 11.5")*, bigger payload, stronger frame.

There are some obvious visuals also, including the grilles and hoods (1500 grille and hood on 2500, larger grille and powerdome hood on 2500hd).


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## buckwheat_la (Oct 11, 2009)

Newdude;1030297 said:


> 2500:
> 
> GVWR 8600lbs
> 
> ...


is the gearing the same between the 1500hd rear end and the 2500hd rear end?


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## Newdude (Dec 4, 2006)

buckwheat_la;1030304 said:


> is the gearing the same between the 1500hd rear end and the 2500hd rear end?


I know you can get the 3.73, not sure on the 4.10. Also, forgot to mention in my previous post:

2500:

- Rear axle is 9.5"

2500hd:

- Rear axle either 10.5" or 11.5"


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## buckwheat_la (Oct 11, 2009)

hey that is interesting stuff, some things i never knew about, i am going to look into the heavier rear ends for my 2 1500hd, mainly because i do a lot of heavy towing with these units.


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## hairygary (Feb 19, 2009)

Anybody know is the front end suspension the same, is it just the frame difference between the two.

my money says B&B has to know.


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## Newdude (Dec 4, 2006)

hairygary;1030328 said:


> Anybody know is the front end suspension the same, is it just the frame difference between the two.
> 
> my money says B&B has to know.


Load rating for the front end is lower. In terms of overall components, they should be similar to the 2500hd (control arms, shocks, etc.) The difference will be in the torsion bars...just my assumption...


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## NICHOLS LANDSCA (Sep 15, 2007)

It's the same truck as a 2000-04? 2500 non HD. Which is the same as a 1989-99 2500old body style. It's been asked over and over.


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## hairygary (Feb 19, 2009)

NICHOLS LANDSCA;1030444 said:


> It's the same truck as a 2000-04? 2500 non HD. Which is the same as a 1989-99 2500old body style. It's been asked over and over.


Yes I understand this and that is not what i am asking. I was asking what makes the front end have a lower load capacity on a 1500HD than a 2500HD. I understand the frame is smaller, but is that the only difference, are all the other front end components the same, because the torsion bars on my truck (based on the rpo code) are the same torsion bars as a 2500HD.


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## NICHOLS LANDSCA (Sep 15, 2007)

hairygary;1030449 said:


> Yes I understand this and that is not what i am asking. I was asking what makes the front end have a lower load capacity on a 1500HD than a 2500HD. I understand the frame is smaller, but is that the only difference, are all the other front end components the same, because the torsion bars on my truck (based on the rpo code) are the same torsion bars as a 2500HD.


But all 2500HD's don't have the same bars. Ever thought they might have DErated the truck. What bars do you have?


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## hairygary (Feb 19, 2009)

NICHOLS LANDSCA;1030454 said:


> But all 2500HD's don't have the same bars. Ever thought they might have DErated the truck. What bars do you have?


The rpo codes show codes on my truck are 6GL and 7GL, which i take to mean it has GL rated torsion bars. From what i have found is that most 2500HD's even the diesels have GL torsion bars, some 6.0's even coming with GK torsion bar. There is only one torsion bar rated heavier than the GL which is the XG and I have heard of very very few 2500hd coming from the factory with a XG torsion bar. I may be completely wrong. My torsion bar rating info comes from the below site.

http://www.gmfullsize.com/tech/torsion401.html

I am trying to find the differences, so I can replace any weaker parts on my front end, if possible.


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## hairygary (Feb 19, 2009)

and yes the thought had cross my mind that the 1500HD is derated, but i do understand it does have a smaller frame, but in all reality it has a 3/4 ton frame, while the 2500HD has a 1 ton frame


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## NICHOLS LANDSCA (Sep 15, 2007)

Eveything I have has GL's except the 97 it has GK's I've never seen XG's on anything. I've looked under 1tons just out of curiosity, My dually has GL's. I'd just hang a plow on your truck and let her buck


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## B&B (Nov 4, 2006)

hairygary;1030449 said:


> I was asking what makes the front end have a lower load capacity on a 1500HD than a 2500HD.


Nothing except that the lower GVWR of the 1500HD also lowers the FAWR, thus limiting the available remaining capacity that's left to carry the weight of a plow without going over.

But the front suspension components are virtually the same between a 1500HD, 2500 and 2500HD. Even the T-bars in many cases can be exactly the same since the T-bars do not determine the FAWR. Using your truck as a perfect example, yours is equipped with the already higher rated GL bars, just like most 2000-2007 2500's and 01-07 2500HD/3500's. So you can clearly see T-bar ratings have nothing to do with actual FAWR.


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## hairygary (Feb 19, 2009)

B&B;1030509 said:


> Nothing except that the lower GVWR of the 1500HD also lowers the FAWR, thus limiting the available remaining capacity that's left to carry the weight of a plow without going over.
> 
> But the front suspension components are virtually the same between a 1500HD, 2500 and 2500HD. Even the T-bars in many cases can be exactly the same since the T-bars do not determine the FAWR. Using your truck as a perfect example, yours is equipped with the already higher rated GL bars, just like most 2000-2007 2500's and 01-07 2500HD/3500's. So you can clearly see T-bar ratings have nothing to do with actual FAWR.


Thanks, I just wanted to know what was different. So then since it is only the smaller frame which gives it the lower weighted front end, I feel a little better about hanging my boss 8-2 poly V with wings off the front end.


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## buckwheat_la (Oct 11, 2009)

i well also point out at this time, (so i was told by someone in the USA when i went looking for information) the main purpose behind the 1500HD was to offer a 3/4ton that could be registered as a 1/2 ton, it had something to do with laws in some states which considered a 3/4ton a commercial vehicle and that the tow ratings on the 1500HD were as such primarily to put it right at the edge of the limits set out for a 1/2 ton, but to allow consumers the confidence that their (1/2ton) was capable to pull larger things, Boats, Holiday trailers, etc. Now i don't have proof of this, i am getting this as knowledge from a chev dealer in Montana, but i don't see why he would lie about it. Anyone ever ask why all the 1500hd seem to always be loaded with options? because they are primarily used for families to pull their expesive toys.

Interesting side note, supposedly there is a 1500hd that has the duramax in it, anyone heard of this mystical beast.


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## tuney443 (Jun 25, 2006)

buckwheat_la;1030565 said:


> i well also point out at this time, (so i was told by someone in the USA when i went looking for information) the main purpose behind the 1500HD was to offer a 3/4ton that could be registered as a 1/2 ton, it had something to do with laws in some states which considered a 3/4ton a commercial vehicle and that the tow ratings on the 1500HD were as such primarily to put it right at the edge of the limits set out for a 1/2 ton, but to allow consumers the confidence that their (1/2ton) was capable to pull larger things, Boats, Holiday trailers, etc. Now i don't have proof of this, i am getting this as knowledge from a chev dealer in Montana, but i don't see why he would lie about it. Anyone ever ask why all the 1500hd seem to always be loaded with options? because they are primarily used for families to pull their expesive toys.
> 
> Interesting side note, supposedly there is a 1500hd that has the duramax in it, anyone heard of this mystical beast.


Never heard of that mystical beast.Probably because of the mystical part.


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## REAPER (Nov 23, 2004)

Bringing the subject up again.

Will replacing the GK T-bars with either GL or XG make it stiffer or just increase load capacity or both? 

What does the torque rating have to do with them?

GK torque rating 8615#


GL torque rating 8782#


XG torque rating 9054#


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## 1500hdcntryboy (Jan 4, 2010)

Someday when the 6.0 on my 1500HD dies i wanna see if i can't get a duramax with and allison in there, that would be awesome.


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## Q101ATFD (Oct 24, 2006)

REAPER;1045652 said:


> Bringing the subject up again.
> 
> Will replacing the GK T-bars with either GL or XG make it stiffer or just increase load capacity or both?
> 
> ...


Upgrading the torsion bars will not increase the plow worthiness of your truck, unless you upgrade the other components to match (depending on truck: front end parts, rear end, engine/tranny, GVWR, etc...). It may, or may not, increase the load capacity of the front end. Technically, your FAWR is limited by what is on the door sticker; end of story - sometimes the door sticker is limited by the components, sometimes by limited by the torsion bar rating, and sometimes by the GVWR - there's no sure way to know how the engineers at GM determined the FAWR for each truck.

The 'torque rating' for the torsion bars is the maximum amount of torsion that the bars are rated for, presumably in foot-pounds (ft*lb), but that site does not cite a source or unit so there's no way to tell. It also doesn't state whether that's for the pair or for each one.

Without a source or unit, all you can use from the torque numbers is to say that the XGs are 3.1% stronger than the GLs.


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## hobbyjeep (Dec 11, 2003)

If parts are same as 2500, GM will often de-rate an axle for various reasons. Since GVWR ratings are based on wakest component, most likely the tires on your vehicle are what limited the axle rating. This is done with Medium Trucks all the time... same hardware with weaker tires.

I too have a 1500 "HD", older model with a 6.5L Diesel... but everything in drive train is a 2500 truck. Makes a nice plow rig.


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