Differences between K1500 with K3500 frame.

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Steve Addy

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Hey all
My 94 K1500 6.5TD frame is rotting out and I have an opportunity to get a K3500 frame that's in decent shape. I understand there are some differences between the two in the front but I can't find a list of those beyond 1) upper control arms / bj's are different, mounting points for the front diff may be different and mounts for the upper control arms might be different. These are both SRW trucks and if I use 'HD' in this context I don't mean the 3500HD (completely different beast) I mean Heavy Duty vs Light Duty (8 bolt wheels vs 6 bolt).

I am wanting to keep the K1500 LD front / rear diffs but use the K3500 HD rear springs, front suspension and frame. I'd think about keeping front / rear diffs but it's a 4.10 and I like the 3.73 and I don't pull much over 2-2.5 ton so I really don't need the 4.10. However, the K3500 rear axle is the 14 bolt full floater with the gigantic drum brakes, which are awesome.

I'd consider keeping the K3500 diffs but I have no history for this vehicle and it was apparently a service truck of some sort because there's an hour meter under the hood.

Anyone know any other differences that are really show stoppers on this please post up, I'm curious to hear what people have to say about this. Around here you don't see K3500 SRW trucks very often. Oh and both are reg cab long bed SRW trucks too.

I'm sure in the end this is going to be a labor intensive horrible project but before the K3500 goes away I thought I'd check to see what others thought about it.

Thanks
Steve
 
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evilunclegrimace

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The mounting points for the front diff ARE different. If you are going to go to the trouble of a body swap from 1500 to 3500 I would suggest running the entire 3500 drive train. It would be ALOT simpler and you might find that you like the 4.10 gears with the 6.5 from an acceleration stand point. Also the 3500 braking system is much better especially if you are towing with it.

The other thing that comes to mind is the "U" joint compatability. Your 1500 power train uses a smaller "U" joint that the 3500. There are "U" joints that will allow you to mate you LD power train to the HD drive train.
 

tpass

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yep, cab swap would be the way to go unless the 3500 drivetrain is completely warn out. Usually anything that has an hour meter is because it does a lot of idling, how many hours are on the meter?
 

Supercharged111

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I'm just here to agree with what's already been posted. That front diff/suspension/brakes don't just swap over and there are more reasons to keep the 8 lug stuff than not. You already have the 4L80 trans and 9.5" rear diff in your current truck, so it wouldn't be as dramatic a change as if you were to swap over from a gasser with 4L60 and wimpy ass 8.5" rear diff.
 

Steve Addy

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yep, cab swap would be the way to go unless the 3500 drivetrain is completely warn out. Usually anything that has an hour meter is because it does a lot of idling, how many hours are on the meter?
The odo says 211k and I didn't take note of the number of hours but I'll look at it tomorrow.
I'm just here to agree with what's already been posted. That front diff/suspension/brakes don't just swap over and there are more reasons to keep the 8 lug stuff than not. You already have the 4L80 trans and 9.5" rear diff in your current truck, so it wouldn't be as dramatic a change as if you were to swap over from a gasser with 4L60 and wimpy ass 8.5" rear diff.
I could go that route but it's a lot of work to handle something that big by one person...and usually it's just me.

I'm not opposed to going that route, it just means there's a lot more unknowns and I'd have to get some more wheels and tires too. It's a lot for one person to manage with honestly, and I usually work by myself because of where my shop is in relation to where I live, but I've made some friends there that I can probably convince to come help me if I need it.

Thanks for the comments, I'll check out the hours tomorrow and see what it will cost to add the front / rear diffs.

Steve
 

BNielsen

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I think @98chevy2500SS did perform a 9.25 front diff swap as well as doing some fabrication to change his entire front end to 2500 control arms. Don't know if he's still around though?
@83GMCK2500 did an entire cab swap on his 96 K3500 after it got wrecked; could peruse his thread for motivation?
 

Nad_Yvalhosert

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I have installed more hour meters on fleet vehicles than I can remember.
Congratulations.
Was this hour meter a GM OE part, found in the manufacturer service manual for said vehicles?

I suppose I could restate my aforementioned post:
Ill be astounded if you can actually find an hour meter --- installed as a factory option ---. On any GMT400
 
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