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Discussion Starter · #1 · (Edited)
This isn't going to be a fast moving build thread, I'm just now in the planning phase. Recipient has just been purchased. I've read a bunch of the build threads and all have some good info and detail but what I'd like to do with this is be "open kimono" about material list/cost and DIY labor required.
While I'd like to go LBZ 6sp, I'm willing to go LLY 5sp.
What I have now:
2004 Suburban 2500 4x4, 8.1/4l85e, 4.10 gears-151k miles
6" Fabtech lift upgraded tierods, new 35" Toyos/AE wheels, AMP power steps, Kenwood Double DIN DDX-790
All in with registration I'm in it for $9500.
I've got a punch list of small items to get it where I want it:
New rear bumper $210
Steering wheel stereo control module-$45
Backup camera and wireless adapters-$60
New drivers seat foam and leather seat bottoms Drvr/Pass- $370
windshield wash reservoir assy- $45
Climate control panel- $85
Passenger seat recline switch-$25
All of these have been purchased so I'm at: $10340
 

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Discussion Starter · #2 · (Edited)
I've got some experience buying a drivetrain package experience with buying the LBZ set up for my FMC Motorhome swap (working awesome so far).
I'm just now starting to see what's available. I know that some on here have used CoPart to buy donor vehicles, I saw this one here local to me: https://www.copart.com/lot/34986966/
Any downsides to buying thru them?
I've got a few other leads of "pullout" packages.
I'm also kicking around the idea of the 2500hd front clip swap at the same time.
I'll update this as I make progress/need help.
I'm also interested in putting a list of materials together for items that you need for the swap but don't come with a donor vehicle, any input on this would be appreciated.
 

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nice burb for the transplant. the wrecked truck looks like a good donor
 

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No issues with copart. If it is local you can go inspect it before the auction so there are no surprises if/when you win the auction. Just make sure you know how the bidding process works (make sure you have the money in your copart account to be able to big up to what you want, and understand the fees) and you should be good to go.

If you want a good overview you can watch the video below.
 

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Discussion Starter · #5 · (Edited)
Great video, Thanks!
I'd like to get an idea of how much fabrication is required to get the duramax to bolt into the 2500 suburban frame:
1. Motor mount towers have to be modified/relocated?
2. Oil pan modification/clearance issues?
Is a body lift required? I've already got 6" of suspension lift and no desire to go higher. I suppose I could dial down the torsion keys and use small blocks in the rear to make that a wash..
I've seen a few methods for conquering the fuel pickup/fill. Has the nut been cracked on what the best fix is for that? I haven't seen a good thread on what all fuel tank mods need to be done.(Edit-I found a thread on modifying the stock forward pickup with the larger tube)

I've read that the tuning to get the tank levels to read correctly is out there, I have HPTuners software(I know EFILive would be better but I've had it for years for my LS projects) and would like to tackle this on my own.
After thinking it over I'm leaning away from buying an entire donor vehicle, I've pushed my luck with my motorhome conversion and my neighbors patience so I'm just going to get a "pullout package", which is what I did with the motorhome and had no problems.
 

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From the rear of the front doors to the frame horns, the frame of the 2500 Suburban and the 2500HD is the same. No changes to motor mounts or anything else have to be done. No cutting or fitting. Rear cross member has to move slightly more than a inch. Only reason for the body lift on the front end is the cooling stack and turbo mouth piece height.
I followed your transplant on your FMC and you will not have any problem.
As far as not buying a complete donor... Lots of stuff that you will find really handy if you have the complete donor, saves lots of leg work.
 
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Also, need to think about 4:10 gears in a Duramax with 5 sp. Consider 3:70 and that 6 speed option. And consider the better head gaskets in the late build dates of the LBZ. The LBZ complete package is a better choice overall, in my opinion.
 

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Discussion Starter · #8 ·
All great advice, I'm definitely looking for an LBZ, but didn't want to completely discount LLY's if there was a great deal on a low mileage package, with the 35" tires it brings the effective gear ratio back a little closer to stock, but of course the extra overdrive would really pay off on mpg for longer hwy drives..
I think I located an LBZ pull out last night that is fairly close and less than 100k miles which is getting tougher to find..
 

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With everything equal, I'm not sure that the 6spd offers much as to fuel mileage, but it does give a more quite driving condition on the highway from less engine noise. The big plus is the tap shift and a little smarter tow haul option. Most of my mileage is with a ~9K lb trailer and the tap with turbo is very helpful.
Low mileage donor are very hard to find at anywhere near a reasonable price. Takes a lot of digging and time, than the distance afar factor. I was fortunate and was able to contact the previous owner before I put in my max offer.
 

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Buy a donor 2500HD. That'll give you all the parts/wiring needed. Starting with a 2004 Suburban, Id find an LBZ/6 speed and not look back. Just swap the rear axle if you're worried about the gearing.

After seeing your skill with that motorhome swap, this will be easy-peasy for you. Completely straightforward swap.
Id bet when you're done you'll ask yourself, "Why was I worried about anything?"
 
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...with the 35" tires it brings the effective gear ratio back a little closer to stock...
Testdrive’s experience is far superior to mine, and my first inclination is to defer to his opinion, sooo…..I could very well be wrong about this, but my arithmetic and those 35” tires make that 4:10 gear look pretty good to me. Especially if you are going to be using the rig for off roading adventures, and more so if you should go with the Ali six speed. As long as there is no heavy hauling anticipated for the ‘burb I wouldn’t even swap out the 10.5” rear for a donor’s 11.5”. I see no real benefit in exchange for the extra hassle of modifying the big rear to fit.

I’m too lazy to search for the thread but there is a thread with the dimensions of the spacers needed for a “reverse rake”. It lifts the front of the body the necessary 2” needed for the LBZ rad support without unnecessarily adding a bunch of height, and giving the illusion to the eye of merely leveling the truck. It would also be needed for a 2500 HD front clip swap.

When it comes time to hook up the rear AC lines you might want to check out this post by 96Sub. I’d like to know if it will work or not (before I have to try it :HiHi: )
Duramax Suburban Brotherhood

And, great job on that FMC repower:thumb:
 

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I've got the 10.5 in mine with a stout EFI Live tune and over 50,000 miles with no problems at all. I researched the difference in the two and the biggest reason for the 11.5 is it has a better weight capacity because of larger axle bearings and housing but that's so they can have a higher rear axle rating. The 11.5 doesn't have the pinion support like the 10.5. which helps keep pinion alignment under load. I also have the reverse rake and the Suburban sits like it should have from Chevrolet up just a little in the rear.
 

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Blackart got it right.
With the 34" vers a ~32" tire the RPM difference is not significant enough to warrant a gear change and of course you can do the correction in the computer.
One problem associated with engine swaps is exhaust drone. So another item to think about. I had it in the beginning even with a stock reuse system, but was able to remedy the problem with some weight added. I would suggest leaving the cat in place. Especially where you live.
 

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Discussion Starter · #15 ·
I have this rig registered under my out of state business so I have some flexibility on EGR and exhaust, not sure what I'll do with it but I'm no fan of the EGR system on these engines, it cokes them up something fierce.
I had a 06 2500hd that was straight piped, it occasionally droned with the stock tune but not too bad, when I switched to the Predator 65hp tune that went away. I do want this to be a quiet ride though..
 

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I built an 05 suburban with the LBZ/6spd and it has been a great truck so far. I am running 3.73 gears with 285/75r16 (32.5) tires and that is about as much as I would want to go if you are doing any kind of towing. If you are running 33" or larger I would stick with the 4.10 gears. On the hwy the LBZ will lug any grade without shifting if its just the family, but when I am towing my skidsteer or dump trailer, I sometimes wish I had the 4.10's. However, I only tow trailers 10% of the time so I can live with not winning any stoplight drags while towing my dump trailer. I know this sounds counter intuitive, but I had an old lifted superduty that I was running 37's on and when I went from 3.73's to 4.56 gears, my mileage actually IMPROVED .5 mpg because the the truck wasn't fighting the high gears. Now that is for drastically taller tires. If you have tires anywhere near stock size, the 3.73's will always give you 9% better mileage because your engine is turning that many lest rotations per mile. Hope this doesn't confuse the the decision even more...
 

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I didnt think about his tires. You guys are right, the 4.10s with those 35s would be a good fit.
 

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Discussion Starter · #18 · (Edited)
Most of my time has still been focused on the motorhome project but I've been watching for a good deal on either an entire truck or a complete LBZ package. Yesterday I made a deal with a local guy who had planned a conversion project and then decided to go another way.
Package includes:
Eng/trans/T-case
All engine bay and all dash wiring harnesses, fuse-blocks, relay panels,and computer modules
Entire cooler pack and core support and all associated hoses/lines
Driveshafts and rear axle
Fuel Tank, cooler and lines
Steering box
Coolant Tank
Intake Filter/system
Steering Column
Dash Cluster and 4x4 Switch Assy
It has 156k miles(Suburban has 153k) but looks like 40k miles, super clean and obviously always a SoCal rig that was well cared for. At $5100 delivered it was a no-brainer.
This brings the project total to $15440. I've got a trip to Moab coming up with the motorhome and my jeepster so I won't be actively working this until later this year.
 

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Thats a great deal. I am in the planning process for my 03 2500 burb. It will be a long while, but I feel like alot of the help will come from the planning stage on how smooth the conversion is. Keep good pics and info please! I will be watching!
 

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That was a good deal. Dont forget the throttle pedal and harness.

I really like how you go about your builds. Really no wasted time, everything well thought out first. GLWB!
 
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