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I've read that the 6.5 will bolt right up in place of the 6.2 but will a duramax also just bolt right in to replace the 6.2 in my '86 3/4ton 4x4 with manual transmission?
 

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Im not to sure that the clutch would be able to handle the torque. But i also would think the flywheel and clutch would be much bigger on a max.
 

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NO!

The Duramax will not directly bolt in place of the 6.2 or 6.5.

The 6.2 and 6.5 are the same size dimensionally (externally of course) and have all the same mounts for accessories and components.

The Duramax is a totaly different engine design, but it does share the same bolt pattern for connecting the transmission bellhousing to the engine. The engine mounts, size, and other details are different.

But given lots of $ and time, I'm sure you can make it happen.
 

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I've read that the 6.5 will bolt right up in place of the 6.2 but will a duramax also just bolt right in to replace the 6.2 in my '86 3/4ton 4x4 with manual transmission?
\

I WISH! I looked into the upgrade for the hummer - $45k. The engine/tranny combo is longer (not sure about using your existing manual - lbz is 650 ftlbs of torque) You would probably need to replace your xfer case as well, then the front and rear driveshafts because of length differences. It not a simple swap unfortunately.
 

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If the Van with the Dmax is out, the parts are there. It runs the normal GM transmission. It's supposed to be a "derated" version of the Dmax to work with the smaller transmission.

Electronics are the worry. How much you would have to change is beyond me.
 

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Ummm... No. Then again, why would you want it to? The 6.2 is more powerful! Just kidding...

Anyhow, no it won't bolt right in. It probably wouldn't be too bad if you wanted to do some cutting and welding. You would probably need a wrecked donor truck to get the Dmax and all of its electrical junk out of.
 

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a guy at my work has a 93 1 ton long bed, and he just bought a dmax rollover and is converting his 6.5 to a 6.6. I think he's crazy.
 

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PM Wayne87Dmax or Nick87Dmax (I think thats their screen names, or something similar) on this site and ask him if it is a direct bolt in he put one in a 87 CC LB for truck pulling. (I'm being veciscious, it was NOT easy or cheap) I think he told me he has over $15K in it all together, including some performance stuff though. While that is cheaper than buying a factory Dmax powered truck, it is no where near as convenient. That said, it is still my dream to have a 70-72 or 83-87 Chevy with one in it.

Good luck if you go for it.

C-ya
 

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What I've often wondered is
Can the allison 6 speed auto be retroed onto a 6.2 diesel?

It seems like one could gear the sucker up and do 1.2k RPMs on the highway while still having a good low range and due to the lockup get much better mileage (maybe not) and have a much more reliable transmission option. (furthermore around here a rebuilt ally is about $500 more than a "GOOD" rebuilt 700r4)

Something a little strange I might mention is that I had my 89 6.2 running with a 2.8 car rearend and a 700r4 (which killed it quickly) but my truck seemed to accellerate and have MORE power than with the lower 3.7 rearend and got around 24-26mpg's consistently. Not really sure why more power, could just be my old reared was totally shot.

My dream is to get a recked new 2006 suburban, fix it and put a 6.2ltr diesel with an allison tranny for :)

Cheers
Ryan
 

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It is a really cool thought, ive pondered it myself. would be a sleeper truck..keep your 6.2 badges on the truck and have all that power under the hood.
 

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Back when David Kennedy(Editor of Diesel Power Magazine) was the tech editor at Petersen's 4 Wheel & Off Road magazine, he looked into putting a LB7/Allison into his '82 K5 Blazer which originally had a 6.2 in it. After he found out how difficult of a swap it'd be, he scrapped the plan altogether and swapped in a supercharged 6.0L Gen 3 gasser with a 4L80E in the rig.
 

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What I've often wondered is
Can the allison 6 speed auto be retroed onto a 6.2 diesel?

It seems like one could gear the sucker up and do 1.2k RPMs on the highway while still having a good low range and due to the lockup get much better mileage (maybe not) and have a much more reliable transmission option. (furthermore around here a rebuilt ally is about $500 more than a "GOOD" rebuilt 700r4)
That would be quite a project. I don't think it would be worth it, though. The Allison is all electronic, which would make the swap rather difficult. You would have to come up with some way to control it. I don't know if the Allison's computer controls are provided by the ECM for the Duramax, but I would guess that they are. That means you would have to create some sort of computer to control it. Not worth it.

Also, I don't think that the 6.2 really has enough power for 70+ mph driving at 1200 rpm. It might be able to do it, but it could get WORSE fuel economy. If you wanted to get fuel economy and turn low rpm, the 700R4 works good. It's got a lockup converter, overdrive, and all that, but it still keeps the engine in its powerband. It might not be the absolute best for heavy towing, but you would never be able to tow much with the Allison setup either. At 1200 rpm you wouldn't be towing much more than an HO scale model railroad car!
 

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The ally (dep on model) has a wide gear range, it could be geared to have a towing gear of 3rd or 4th and double overdriver :) w/ the correct rearend

This is just one of those things that would have been nice if it came from the factory that way. :lol:

Cheers
 
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