Chassis Swap - 1500 on 2500 frame?

[jmoore3117]

Hello CAFC! I am new to this forum, and this is my first time posting, so please bare with me.

I've been all over the internet and surprisingly this day in age, haven't found any builds of what I am looking to do. I have a 2005 Avalanche 1500 Southern Comfort conversion truck. I got it for a steal because it had a bad transmission. I put a 3.73 planetary 4L65e i got out of a Suburban in it only to find out later that MY truck is factory equipped with 4.10s. Needless to say it has some issues. The transfer case I got with the trans does not match the truck (the truck is the dual-connector, transfer case is the single 8-pin) and I'm not sure the case is 100%. The 5.3 I'm sure is wearing out (although it still has NO issue breaking both tires loose) with 200k miles. Last, but not least let's be honest....its a half ton....

I have an opportunity to get a chassis (truck was wrecked, body wasted but chassis is A1) 2005 (im pretty sure?) Suburban 3/4 ton with the big block 8100/4L80e combo, 4.10 axles, 4WD, etc. Instead of rebuilding mine the way it is which will cost about double what ill get the big block chassis for, is it possible to just unbolt my cab and bolt it on to the suburban chassis? Has anyone had any experience putting a 1/2 ton cab on a 3/4 ton chassis, meaning is there even a difference or all cabs the same? I know that the Burban's/Lanche's share the same chassis, but are they bolt-for-bolt the same? I'm wondering what all is involved with this swap so that I can properly prepare. I am a mechanic in a customs/resto shop with lifts so tooling is not an issue. I am also a former motor controls technician, so electrically I understand re-pins, etc. Any advice/experience/procedure would be GREATLY appreciated. Thanks!

 

[Chevymike2003]

I've never even thought about doing something like that before. It sounds like a pretty cool idea though. Since the avalanche came in the 8.1 I would imagine that would be the same chassis as the suburban that comes in the 8.1. Unfortunately, I can't be all that much help so I'm not sure. The only thing i'm thinking of is stuff like the Suburban probably has rear a/c and probably has A/C lines that go to the rear of the cab. But if you gutted everything I would imagine you could make it work.more If you do decide to do it definitely take pics and post them! Myself and I'm sure a lot of others would like to see them. I'm sure others will chime in and give there $.02 Good luck!

 

[redheadedrod]

Different sheet metal although similar. 2500 Avy came with leaf springs, 1500 with coil rear springs. There are other threads where this has been discussed. Not impossible but will be more difficult than you would imagine. You may find clearance issues and frame mounts that don't line up. If you are a good fabricator nothing out of realm of possibility. Might even be able to pick up some 2500 parts where necessary.

Rodney

 

[jmoore3117]

Thanks for the input guys! I will definitely be taking step-by-step if i decide to pull the trigger on this thing. And yes my boss and I are pretty good with fabrication I just didn't want to chop the frame or any of that. Moving body mounts shouldn't be that difficult of a task. And yes I am well aware of the rear suspension differences after hauling a bunch of wood for a friend this weekend lol. Definitely in need the rigidness of a 2500. I hate to lose the get up and go of the SBC though. Pretty impressed with the 5.3 paired up with a 4.10 axle...

 

[MS03 2500]

A couple of things you need to know

2500 burbs came in 2 favors 6.0 or a 8.1.
You are going to find a issue with cooling, the 8.1 is way bigger than 5.3 and it extends further forward. If you try to use the 1500 radiator support the engine will not fit.
So see if you can get the support and radiator from the donor.


On yeah the inner fenders are different too.

One more thing the frame horns are different from a suburban.(Bumper Mounts)

 

[camaroz1985]

Won't just bolt on, but not terribly difficult if you are a competent mechanic/fabricator.

There are 3 main things you will need to do.

1.  A couple body mounts are in different locations, but they can be made to work.
http://www.dieselplace.com/forum/7434657-post603.html

2.  You will need to switch the brake booster from the 1500 vacuum assist to the 2500 hydro boost.  There is one bolt that is different so you will have to drill another hole (GM dimpled the firewall where you need to drill so it isn't difficult to figure out).
http://www.dieselplace.com/forum/7434665-post604.html

3.  You will need to get 2500 pedals, the booster rod attached differently.
http://www.dieselplace.com/forum/7434673-post605.html

The links are for a 1500 Suburban onto a 2500 frame, but they should be the same.  Like others said you will definitely want to transfer over all the cooling system from the 8.1 as well.

 

[jmoore3117]

Awesome info guys I really do appreciate it. I also found out there may be another 2500 Avalanche frame available so maybe that will help with the body mount situation. it makes perfect sense with the cooling setup, although I cant say I would have thought of it until trying to mate the body and chassis together. I will be checking out the frames this weekend and begin making a list of things to do. Hopefully breaking ground on this project soon! Really loving this forum already and how helpful and knowledgeable the guys are here. Thanks again!!

 

[frito]

If you decide to pull the trigger, make sure to create a build thread and post pictures and progress.  I would love to  follow the build.

 

[TheSpartanKnight]

If you decide to pull the trigger, make sure to create a build thread and post pictures and progress.  I would love to  follow the build.

I second this.

I started the discussion in the 2nd Gen section about this very thing. It'd be great in several years to find a rolled 2500 'Burban where the powertrain and chassis are still golden, and put an Avvy body on.

 

[camaroz1985]

I second this.

I started the discussion in the 2nd Gen section about this very thing. It'd be great in several years to find a rolled 2500 'Burban where the powertrain and chassis are still golden, and put an Avvy body on.

I have thought about that a lot, with a Duramax swap for good measure.

 

[TheSpartanKnight]

I have thought about that a lot, with a Duramax swap for good measure.

Dude, no kidding, I was daydreaming this weekend as we were moving (so while in and out with boxes) about a YouTube video doing EXACTLY that with CAFCNA members there on camera from around the nation to help out.

Take an LTZ (because might as well have the creature comforts) that the powertrain is just shot on as well as rust issues.
Find a rolled 2500 Suburban where the body is bent and has totaled the rig, but the chassis is still good. Maybe some spindle issues.
A 2500 HD Duramax Silverado/Sierra that has been demolished from the C pillar back. Like that back half is missing. So we replace the driveline...

I'd love to try this in about a decade when my Sixer is wearing out. I'm not even a fan of diesel, but the one of a kind build would warrant it I think.

 

[JVZL1]

2.  You will need to switch the brake booster from the 1500 vacuum assist to the 2500 hydro boost.  There is one bolt that is different so you will have to drill another hole (GM dimpled the firewall where you need to drill so it isn't difficult to figure out).

Did they not switch to hydro boost 0n the 1500 04 or 05.

 

[ygmn]

....
Did they not switch to hydro boost 0n the 1500 04 or 05. [/color]

I do believe so....

 

[Alaska_AV.]

kinda enjoying this...

 

[JVZL1]

kinda enjoying this...

I could hear you giggling when this was first posted.

 

[MS03 2500]

I could hear you giggling when this was first posted.

X2 It's an annual post, springtime folks start thinking about Mods.

 

[HellHoof]

I just saw the newest post from Dirt Everyday on YouTube announcing their plans on what to do with the Avy they smashed up in a video a few months back. They're going to do a Chassis swap from a 2500 to a Yukon XL. The second I saw the video, I remembered this thread and wanted to share the link with you. May be worth looking into...heck, you may be able to reach out to the guys and get some info/assistance or help them out/get on the show/get famous/forget all of us small people on CAFCNA.

https://www.youtube.com/watch?v=CeJSX2MK6D8

 

[Oberloh]

Dude, no kidding, I was daydreaming this weekend as we were moving (so while in and out with boxes) about a YouTube video doing EXACTLY that with CAFCNA members there on camera from around the nation to help out.

Take an LTZ (because might as well have the creature comforts) that the powertrain is just shot on as well as rust issues.
Find a rolled 2500 Suburban where the body is bent and has totaled the rig, but the chassis is still good. Maybe some spindle issues.
A 2500 HD Duramax Silverado/Sierra that has been demolished from the C pillar back. Like that back half is missing. So we replace the driveline...

I'd love to try this in about a decade when my Sixer is wearing out. I'm not even a fan of diesel, but the one of a kind build would warrant it I think.

In 2005 a couple mechanics in Elkhart Indiana took a 2500 4wD and put a Dana 60 in the front hung on leaf springs. They also dropped in a duramax. Your may have seen it a a Mag, cresting a hill a while back, I think they were running 44 s but I could be mistaken. I sorry I don’t have the Magazine info or what they did to reinforce the frame though.

 

[MS03 2500]

Believe it or not, there is a guy who actually did drop an non-cladded 1500 body on a 2500 frame. I don't know if he is a member.

 

[Oberloh]

X2 It's an annual post, springtime folks start thinking about Mods.

How did your Chassis swap go? Let me know so I can use your experience to do mine. Instead of a 2500 though (which is my last choice) I like the '80 series 2500 Suburbans that have live axles still. I even saw one with a Dana 60 and 14 bolt rear end. I only what the frame and axles to wheel hubs, well maybe the tranny...ok everything heavier duty than my 1500. Maybe I'll just keep my body...lol

 

[Oberloh]

Hello CAFC! I am new to this forum, and this is my first time posting, so please bare with me.

I've been all over the internet and surprisingly this day in age, haven't found any builds of what I am looking to do. I have a 2005 Avalanche 1500 Southern Comfort conversion truck. I got it for a steal because it had a bad transmission. I put a 3.73 planetary 4L65e i got out of a Suburban in it only to find out later that MY truck is factory equipped with 4.10s. Needless to say it has some issues. The transfer case I got with the trans does not match the truck (the truck is the dual-connector, transfer case is the single 8-pin) and I'm not sure the case is 100%. The 5.3 I'm sure is wearing out (although it still has NO issue breaking both tires loose) with 200k miles. Last, but not least let's be honest....its a half ton....

I have an opportunity to get a chassis (truck was wrecked, body wasted but chassis is A1) 2005 (im pretty sure?) Suburban 3/4 ton with the big block 8100/4L80e combo, 4.10 axles, 4WD, etc. Instead of rebuilding mine the way it is which will cost about double what ill get the big block chassis for, is it possible to just unbolt my cab and bolt it on to the suburban chassis? Has anyone had any experience putting a 1/2 ton cab on a 3/4 ton chassis, meaning is there even a difference or all cabs the same? I know that the Burban's/Lanche's share the same chassis, but are they bolt-for-bolt the same? I'm wondering what all is involved with this swap so that I can properly prepare. I am a mechanic in a customs/resto shop with lifts so tooling is not an issue. I am also a former motor controls technician, so electrically I understand re-pins, etc. Any advice/experience/procedure would be GREATLY appreciated. Thanks!

Boy, do I concur with you about 1500's being 1/2 tons. Lightweight ones at that. Every week or so since '03 I find myself remembering that I should have waited to find a 2500 model back in 03, instead of jumping into the limited edition 'yellow' model 1500.
But now, at 220K miles, I know each and every part that I have replaced, maintenance performed and mild abuse thrust upon my Av. I too have been looking for a decent condition 2500 suburban (square body with two live axles) to restore and swap bodies with. When you complete yours I'd love to learn from your experience.

Thank you

Don

 

[Oberloh]

2. You will need to switch the brake booster from the 1500 vacuum assist to the 2500 hydro boost. There is one bolt that is different so you will have to drill another hole (GM dimpled the firewall where you need to drill so it isn't difficult to figure out).

Did they not switch to hydro boost 0n the 1500 04 or 05.

Thank you for the advice. It's going into my folder until I make the conversion.

 

[Oberloh]

A couple of things you need to know

2500 burbs came in 2 favors 6.0 or a 8.1.
You are going to find a issue with cooling, the 8.1 is way bigger than 5.3 and it extends further forward. If you try to use the 1500 radiator support the engine will not fit.
So see if you can get the support and radiator from the donor.


On yeah the inner fenders are different too.

One more thing the frame horns are different from a suburban.(Bumper Mounts)

Lots of good info. Thinking that the Avalanche was on a Suburban frame, I ordered aftermarket bumpers for a suburban and ended up having to fabricate mounts for it. Still love welded steel bumpers 1000x better than the cladded stamped cheapos it came with.

 

[Oberloh]

I just saw the newest post from Dirt Everyday on YouTube announcing their plans on what to do with the Avy they smashed up in a video a few months back. They're going to do a Chassis swap from a 2500 to a Yukon XL. The second I saw the video, I remembered this thread and wanted to share the link with you. May be worth looking into...heck, you may be able to reach out to the guys and get some info/assistance or help them out/get on the show/get famous/forget all of us small people on CAFCNA.

I would have loved to have been able to buy their 2500 AV before they decided on the Yukon body swap. I have followed them since they started and I love the live axle swap in front.

 

[Oberloh]

If you decide to pull the trigger, make sure to create a build thread and post pictures and progress. I would love to follow the build.

Another Yellow (Harvest Gold or something like that?) Avalanche. Too cool! By the way is your passenger front fender color a shade off from the rest of the body as I have seen so many '03's and 04's ? I spent a lot of time examining mine when it was new on the lot to convince myself it was still new and not repaired.