Reason for Body Lift on 2500HD

[chaddpa]

Sorry if this has been discussed but I've searched and haven't found an answer to a question I have. It appears the 2500HD has a 2" body lift over previous years 2500. Question is why? I thought it might be clearance at the tunnel for the D/A combo but I took a look under one and it appeared similar to one with a 6.0L. I'm interested in a new work truck and thought something like the 2500 ECSB looked ok only to find its no longer made. The HD looks good too but I'd rather have easier access over the bed rails without resorting to running boards. It looks like the HD cab mounts are postioned higher on the frame rails than the 2500 so lowering the cab/box looks like it might be a bit of work. The 1500HD is only available as a CC so what a fellow to do?

[Frank S]

It's not really a 2" body lift. The 2500 HD and 3500 trucks have a 10" frame while the others have an 8" frame.

 

About the only reason to body lift it would be to clear larger tires but several people are running 285's on stock rims with little in the way of problems.

[chaddpa]

Well it appeared to me that the 2500 and 2500HD had the same 8.5" deep frame rail under the cab. The cab crossmembers on the HD set off the frame rail 2" where the 2500's set right down onto the frame. Not sure how the 3500 frame compares but I thought I had read that the 2500 and 2500HD frames were similar except the 2500's frame reduced behind the rear axle.

[BlackSilver]

Well it appeared to me that the 2500 and 2500HD had the same 8.5" deep frame rail under the cab.

 

No, the 2500HD (and 3500) have a larger frame than the 2500. That's why they look "lifted".

[Mr Mojo]

Well it appeared to me that the 2500 and 2500HD had the same 8.5" deep frame rail under the cab. The cab crossmembers on the HD set off the frame rail 2" where the 2500's set right down onto the frame. Not sure how the 3500 frame compares but I thought I had read that the 2500 and 2500HD frames were similar except the 2500's frame reduced behind the rear axle.

 

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I looked at my HD and my buddies 2500 and what you say is what I observed. The 2500 frame is smaller near the axle.

 

Here's a pic of my 2WD HD next to his GMC 4 x 4 2500

 

[chaddpa]

Thanks for the pics Mr Mojo, sure helps to have two trucks side by side for comparisons like this. I was at a dealer who had a 2005 2500HD and a 2004 2500 side by side which made it pretty easy to compare frames which reinforced my observations stated in my earlier posts. Evidently there has been a lot of discussion on this topic, (after searching on some other forums) with many indicating a "body lift" on the HD and many flatly rejecting it. I didn't intend to open a wasps nest posting my comparison but I think I'm accurate in my observations. It appears that the side rails of frames under the cab of these two trucks are the same depth and gauge but the cab attachment brackets are shifted up on the frame rails an extra 2" on the HD. The frame on the 2500 reduces down over the rear axle whereas the HD continues the same frame depth clear to the back of the truck. To my way of thinking this consists of a 2" "body lift" just not done with spacer under the cab isolation mounts as more typically seen done. So it appears that (at least on the 2005's), GM has the cab/bed lifted up an extra 2" on the HD that may not be essential if you've got a 6.0L engine seeing how the 2500 series didn't have this "lift". I guess I'm still unsure what required the extra cab/bed height on the HD but much of what I've read points to the D/A combo requiring additional clearance at the tunnel. It wasn't obvious to me comparing a HD with D/A to one with a 6.0L auto that there was any difference in clearances there. Perhaps it was motivated by cooling or noise issues with the D/A or 8.1L and was carried across to the 6.0L version too. I can understand GM making the frames common to reduce the number of variations present on the assembly line, but I personally prefer the lower stance that the 2500 series had.