Welding 2500 rearframe onto 1500 frame?

[axisT6]

Why not 2x4? At least keep the same section height.

 

[great white]

Back half of frames rot out first because they live in the road spray from the rest of the truck in front of it. Worse if you're in the rust belt and drive it year round.

If the C channels are still good, easier way out is to just replace the rotted crossmembers.

If the C channels are gone, safer to just swap a good frame under it or part your current truck down for one that has a good frame already under it.....you'll end up with a better/safer end product.

If you elect to cut and weld, make sire you use proper frame joining techniques like fish mouth plates. But welding frames doesn't "cut it"....

Cheers.

 

[benz88]

Why not 2x4? At least keep the same section height.

I didn't measue Yet, So I was guessing it would be 2x3 but 2x4 works.

Back half of frames rot out first because they live in the road spray from the rest of the truck in front of it. Worse if you're in the rust belt and drive it year round.

If the C channels are still good, easier way out is to just replace the rotted crossmembers.

If the C channels are gone, safer to just swap a good frame under it or part your current truck down for one that has a good frame already under it.....you'll end up with a better/safer end product.

If you elect to cut and weld, make sire you use proper frame joining techniques like fish mouth plates. But welding frames doesn't "cut it"....

Cheers.

of course. I've done my fair share of work on frames.

 

[AlNelson]

I don't think that's accurate

From my hands on experience, the 8 lug 3/4 ton chassis is thicker. The chassis rails are taller under the cab and are most likely a bit taller in the bed area. ALL 88-98 truck springs are the same length. The exception is the 3500HD.

The 6 lug 3/4 ton chassis is near if not exactly identical to the 1500. The difference is the rear axle and the springs.

To make life easier, easier, either swap chassis, or find an identical chassis.

Coincidentally, I believe the 6 lug 2500's had a GVWR of 7200, and the 8 lugs with the FF had a GVWR of 8600.

 

[Barrymaxx]

Thanks for the advice guys. Im going to measure it all up this weekend and maybe get the rear section if it looks like it will work. Ive seen a few frame splices online so Ill poke around at the best way to do it.

 

[great white]

Coincidentally, I believe the 6 lug 2500's had a GVWR of 7200, and the 8 lugs with the FF had a GVWR of 8600.

Yup, 8600Lb GVWR 2500's got the full float rear axles....8 lug only.

 

[Barrymaxx]

So got a rear section of frame this weekend. Its a 99 or 2000 3/4 ton 2wd drive. I have it sitting next to my 1500 frame and its really similar. The c chanels are the same height, but the 3/4 ton frame is almost twice as thick it appears.

First problem I noticed is that the cab mounts are 1 1.5" lower than the 4wd ones. I can put a spacer in there to level it out. Then raise the bed accordingly.

Other than that this looks like its going to be a direct swap. Ill take some pictures along the way

 

[96-1500]

I believe frames that were under 8600 GVWR were the same. Thats what ive heard anyways.

In 4x4s, yes. IIRC the 2wd had a slightly lower GVWR, but as a general rule of thumb if it's 8 lug, it's got the heavier frame.

Yup, 8600Lb GVWR 2500's got the full float rear axles....8 lug only.

Not exactly. 8600 lbs could get either SF or FF, just has to do with how they were optioned. From what I've seen, semi-floaters (8-lug) are considerably more common. Around here at least.

So got a rear section of frame this weekend. Its a 99 or 2000 3/4 ton 2wd drive. I have it sitting next to my 1500 frame and its really similar. The c chanels are the same height, but the 3/4 ton frame is almost twice as thick it appears.

First problem I noticed is that the cab mounts are 1 1.5" lower than the 4wd ones. I can put a spacer in there to level it out. Then raise the bed accordingly.

Other than that this looks like its going to be a direct swap. Ill take some pictures along the way

Should work fine...obviously as you've figured out, the difference between the 1500/light duty 2500 and heavy-duty 2500s was the thickness.

If you got the springs, too, keep them. Assuming you use it as a truck, that is.

I'll be interested to see how it turns out!

 

[eric.s.t]

all these guys have valid points.. i think going from 1500 to 2500 rear half of the frame would be a big job for nothing. either just do a cab swap onto the 2500, which is a big job.. but not that bad really. Its easy to pull the cabs off these trucks! Or buy another 1500 back half. Ive alwasy personality wondered why the back would rust out but not the front... must be some hidden rust IMO... but who am i to say, i never seen your truck

 

[96-1500]

all these guys have valid points.. i think going from 1500 to 2500 rear half of the frame would be a big job for nothing. either just do a cab swap onto the 2500, which is a big job.. but not that bad really. Its easy to pull the cabs off these trucks! Or buy another 1500 back half. Ive alwasy personality wondered why the back would rust out but not the front... must be some hidden rust IMO... but who am i to say, i never seen your truck

Yeah, when my frame went, I patched it up enough to get me through a couple months, and then parked the truck.

But lots of people have successfully repaired frames...it's never new again, though.