GMT400 frame styles

[FastOrange]

I didn't see this question answered. The reason that the body is higher on the -800 chassis is because there is a body lift incorporated into the design/construction of the frame. Translation, they welded/rivetted the mounts higher on the frame, or used taller mounts. RPO: HVY = Identification, 2 inch body raise, H.D. model

No, that is incorrect, the 2500HD DO NOT HAVE A "BODY LIFT". they have a 2" taller frame, to clear the Allison transmissions, This applies to the 2500HD/3500 only, regular 2500's do not use the taller frame. When you look under a HD, the frame has the same gap between it and the cab as any other truck, thus the "body raise" is the 2" taller frame.

2500HD and 3500 use same frame but 3500 uses a heavier spring pack and heavier rated t-bars.

as far as difference between a 1500HD and a 2500 in NBS, I have no clue.

 

[83GMCK2500]

I knew I hoarded files from the internet for a reason... I found the dimension guides for 1999 & 2000 chassis & frames, body, interior, dang near everything. Here is a sample:

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1999 Upfitter Guide (.pdf)
2000 Upfitter Guide (.pdf)

EDIT: I see where the upfitter guide is posted and stickied in: "Full Custom Suspension / Cages / Fab" excellent. Glad to see it here.

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[83GMCK2500]

No, that is incorrect, the 2500HD DO NOT HAVE A "BODY LIFT". they have a 2" taller frame, to clear the Allison transmissions, This applies to the 2500HD/3500 only, regular 2500's do not use the taller frame. When you look under a HD, the frame has the same gap between it and the cab as any other truck, thus the "body raise" is the 2" taller frame.

2500HD and 3500 use same frame but 3500 uses a heavier spring pack and heavier rated t-bars.

as far as difference between a 1500HD and a 2500 in NBS, I have no clue.

I will not disagree that the frames are taller, but I don't think the taller frame is the exclusive reason for the taller cab. The frames are also constructed taller to accommodate the higher GVWRs (I'm sure you're aware, just stating it for the record.) Since I was digging around my hoarded files, I found the upfitter manual for the 02 GMT-800s and after flipping thorough it I see that all 1500s roughly have a 6" tall frame, measured underneath the cab; and 2500s have roughly an 8" tall frame. (Makes sense, higher GVWR thing.) In the manual they have front frame section details, showing cab mounts and core support mounts. The K15/K25 front frame section clearly shows the front cab mount surface below what they have labeled Normal Top of Frame. At the front of the frame section forward of the engine crossmember, the core support perches are clearly below the top of the frame in that region. The K25(HD)/35/36 front frame section clearly shows the front cab mount surface EVEN with "Normal Top of Frame". At the front of the frame section forward of the engine crossmember on the HD frame it clearly shows an elevated core support mount.

It seems natural for the frame thickness to increase as GVWR increases, I do not see where this warrants a genuine RPO for it. HVY: IDENTIFICATION 2 INCH BODY RAISE, H.D. MODEL TWO INCH BODY RAISE I.D.(HVY) I would understand where taller or raised mounts warranted an RPO...

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[MYT HI]

Went we went to take off a plow mount off of a 2001 chevy 2500 and put on my dads 2000 1500, the mount wouldn't work because it was made for a wider taller frame


Sent from my 350 TBI powered iPhone

 

[GroundSpeed]

I apologize if this has already been covered, I have to run (heading to the wreckers) and don't have time to read this whole thread.

So I have a reg cab long box 1500 2wd, could I put the body on a 1500 4wd rclb or 2wd/4wd cab and a half short box?

Relocating body mounts isn't an issue for me.

 

[Justin S]

Frames are all different depending on if long or short bed, regular or extended cab. You can swap bodies onto different frames regardless if 2 or 4 wheel, just had to be the same configuration.

 

[GroundSpeed]

Frames are all different depending on if long or short bed, regular or extended cab. You can swap bodies onto different frames regardless if 2 or 4 wheel, just had to be the same configuration.

Good to know thanks for clearing that up!

 

[duallburb]

does anybody have 92-99 suburban frame dimensions or overall same

 

[Hipster]

No, that is incorrect, the 2500HD DO NOT HAVE A "BODY LIFT". they have a 2" taller frame, to clear the Allison transmissions, This applies to the 2500HD/3500 only, regular 2500's do not use the taller frame. When you look under a HD, the frame has the same gap between it and the cab as any other truck, thus the "body raise" is the 2" taller frame.

2500HD and 3500 use same frame but 3500 uses a heavier spring pack and heavier rated t-bars.

^^ This

The 2500/3500 frames are indeed taller height. Taller equates to section width, strength and rigidity.

 

[Hipster]

I will not disagree that the frames are taller, but I don't think the taller frame is the exclusive reason for the taller cab. The frames are also constructed taller to accommodate the higher GVWRs (I'm sure you're aware, just stating it for the record.) Since I was digging around my hoarded files, I found the upfitter manual for the 02 GMT-800s and after flipping thorough it I see that all 1500s roughly have a 6" tall frame, measured underneath the cab; and 2500s have roughly an 8" tall frame. (Makes sense, higher GVWR thing.) In the manual they have front frame section details, showing cab mounts and core support mounts. The K15/K25 front frame section clearly shows the front cab mount surface below what they have labeled Normal Top of Frame. At the front of the frame section forward of the engine crossmember, the core support perches are clearly below the top of the frame in that region. The K25(HD)/35/36 front frame section clearly shows the front cab mount surface EVEN with "Normal Top of Frame". At the front of the frame section forward of the engine crossmember on the HD frame it clearly shows an elevated core support mount.

It seems natural for the frame thickness to increase as GVWR increases, I do not see where this warrants a genuine RPO for it. HVY: IDENTIFICATION 2 INCH BODY RAISE, H.D. MODEL TWO INCH BODY RAISE I.D.(HVY) I would understand where taller or raised mounts warranted an RPO...

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What are you using for hd frame specs? 5 ton type chassis? Yes the cabs are mounted higher for Top kicks etc.

I can't even expand those diagrams you posted to read measurements or any fine print.