Is it a HD or not?? - Off-Road Forums & Discussion Groups
GM Standard IFS Trucks & SUV's All discussion of full sized IFS Trucks, SUV's to include Suburban

LinkBack Thread Tools Display Modes
post #1 of (permalink) Old 02-14-2002, 12:55 AM
Posts: n/a
Is it a HD or not??

OK...I've had enough of trying to figure this out. Ever since the new new trucks came out that are actually designated "HD", either the aftermarket is confused, or I've failed to pull my head out all this time.

As far as I know, my truck is a 2500HD. Does anyone know if that means anything for a '99 or not?? I was under the assumption a 3/4 ton of that year could be either. Trying to narrow down products in the aftermarket has been a nightmare. I've called several of them to ask what they mean, and I get different answers. Some say '99's are either 2500 or 3500 etc etc., and there is no such thing as Heavy Duty versions. They used to do it. What, they decided to stop for 2 years and just make 3 versions of trucks? Bull.

I contacted GM and got the typical "We here at customer service are unqualified to answer...blah blah." Lick me! They said go to my dealer and ask. OK, I'm going to go in and politely ask if they could decipher a jumble of codes in my glove box and cross reference that with some sort of company product spec sheet. I'd feel just as stupid as them when they gave me the deer-in-the-headlight look like I must be kidding.

Anyone have any insight into this ridiculous question? I know I should know my truck, but most of them don't, so I don't feel so bad yet.

Here's a couple clues I have found:

<font color=blue>The warranty booklet that came with my truck actually seperates emission system warranty into light/medium/and heavy duty. The fancy warning sticker under my hood indicates the vehicle is equipped to comply with both heavy and medium duty emissions laws.

It actually says 2500 HD on my window sticker I still have.</font color=blue>

Here's a list of additional upgrades I special ordered from the factory which I feel may or may not change the classification of the truck:

<font color=green>I went with the 6.0L instead of the standard 5.3L
Locking diff's (limited slip really)
4.10 gears
4x4 manual T-case
engine oil cooler
engine block heater
high flow air intake
manual 5-speed with "granny" gear
8600 GVWR (yes, you can order a weight biggest one was 10K, but you had to go 1 ton at that point)
I didn't necessarily order this, but it's an 8 lug (can't remember if that was because it's 4x4 or something else)</font color=green>

My Haynes is no help either. It actually says it covers the '99-'00 1500 and 2500, but NOT the Heavy Duty models. See my dilemma?

Anyway, I would appreciate any help. It IS a weird question [img]/wwwthreads_images/icons/crazy.gif[/img], so at least some of you will get a laugh tonight.

Sponsored Links
post #2 of (permalink) Old 02-14-2002, 03:21 AM
Join Date: Jan 2001
Posts: 4,752
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Is it a HD or not??

what rear axle is it? FF or SF? that would narrow it down a LOT. I'm really not sure exactly what seperates the two though. I"ll bet you can get the little emblems and then just pretend its an HD. sorry i can't help you more

---Peacock posted this
<font color=red>'96, richmond 3.73, detroit rear, cold air, dual flowmasters, new drive-train,</font color=red>
u4ia4 is offline  
post #3 of (permalink) Old 02-14-2002, 05:01 AM
Join Date: Aug 2000
Posts: 7,863
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Is it a HD or not??

Well, for 88-98 trucks, a 6 lug 3/4 ton was a light or regular 3/4 ton. An 8 lug 3/4 ton is a hd 3/4 ton. Which means it has the larger front diff and larger rear diff. Yours is more than likely the HD since it has 8 lugs.

Big Willy Style

Best Auto Insurance | Auto Protection Today | FREE Trade-In Quote
willyswanter is offline  
Sponsored Links
post #4 of (permalink) Old 02-14-2002, 11:01 AM
Posts: n/a
Re: Is it a HD or not??

I thought in '99 they just made the 2500 without the HD designation. I also thought the 6.0L was standard for the 2500. It wasn't until '01 that the 2500HD came out. I'm sure the '99 could be equipped with options to make it a HD.

97 K1500, 4" Rancho, 35" Wild Country AWs, custom dual exhaust
post #5 of (permalink) Old 02-14-2002, 11:29 AM
Posts: n/a
Re: Is it a HD or not??

The earlier body style trucks were available in 7200 GVW (6-lug) or 8600 GVW (8-lug) The '99-00 new body style 2500s were built as the 8600 GVW -so would be considered heavy duty.

The 01-up 2500HD actually has a 9200 GVW so now the 8600 lb trucks are considered the standard 2500

To add more confusion, if you want a crew cab version of the 8600 GVW 2500, GM calls it a 1500HD

post #6 of (permalink) Old 02-15-2002, 01:50 AM
Posts: n/a
Re: Is it a HD or not??

my understanding for the newer trucks is that the 2500 hd is a one ton vehicle without the dual rear wheels.

post #7 of (permalink) Old 02-15-2002, 12:26 PM
Posts: n/a
Re: Is it a HD or not??


I honestly don't know what axles I have back there. Never opened it up yet or paid much attention to that. My Haynes says they should be SF, but it also says it doesn't cover HD models. It's an 8 lug, 14 bolt. That's all I know for now.

I could have sworn I had to special order that 6.0L over the 5.3. The one thing I know for sure is I have a heavy duty emissions system and warranty to cover that.

On the GVWR, it's kind of the chicken -vs- the egg. I ordered all these upgrades, and at some point the GVWR had to go up to 8600. I sat down with guy and said "I want this, this, this, and this, and by the way the heaviest GVWR I can get," and he said, "Yeah, we'll have to go with 8600 now anyway cause of blah, and that's the highest you can get unless you want a one ton."

I know a lot changed from 98 to 99, and then again once '01 came around. Part of my confusion comes from seeing ads that say '99 - '01 lift kit for the 2500, but not the HD, etc. etc. That's easily solved by calling and asking what year HD are they talking about. I just really want to know what I have here.

Thanks for the help guys.

post #8 of (permalink) Old 02-15-2002, 01:37 PM
Posts: n/a
Re: Is it a HD or not??

If your axle looks like the one in the top of the picture you have the full-floater. If it looks like the one in the bottom of the picture it's the semi floater.

[img]/wwwthreads_images/icons/wink.gif[/img]Somebody once said "Go Big" . . . Well we're goin' Full Size[img]/wwwthreads_images/icons/wink.gif[/img]
post #9 of (permalink) Old 02-15-2002, 01:45 PM
Can't Get Enough
A1980GMC's Avatar
Join Date: Oct 2000
Location: McKinney, Texas
Posts: 1,293
Thanks: 0
Thanked 0 Times in 0 Posts
Re: Is it a HD or not??

My roommates 99 3/4 ton work truck has a 14FF. I do not know if it is a HD or not. It is the older 88 and up body style.

When did they start making all of the truck in this new body style they have. I know all of the 1/2 tons in 99 were new body style but all of the Tahoes and Subs were old, like mine.

Does this have anything to do with the confusion? I don't know just wondering.

Laters, Ryan

1999 Suburban 6.5" Cepek Lift and 3" Body lift, 37x12.5x15 SSR's
A1980GMC is offline  
post #10 of (permalink) Old 02-16-2002, 02:38 AM
Posts: n/a
Re: Is it a HD or not??


Thanks everyone. Looks like I have the FF, 14 bolt, with 4.10 locker. I'm gonna have to live with driving some sort of freakish hybrid here, and just watch my step with what I buy.

Thanks, you guys rock. I must wax philosophical for a moment and say that us (meaning you) GM IFS guys have got to be the most versatile mechanical minds out here.

Many A-holes out there fork over the dough for a 30K stock vehicle and turn around and pay someone an extra 10k to make them look cool in it on Hollywood Blvd. (or equivalent in your neighborhood). Very few people know what it means to care about what they drive anymore, and fewer still would know enough to make it better.

I honestly didn't know what to expect when I first asked this question. I was prepared for anything from "Go join Swamper at Truckworld!" to oletater's ever unwaivering, and hilarious, "You're an idiot!" replies. Instead, I learned a lot.

Thanks again,


Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the Off-Road Forums & Discussion Groups forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome