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Discussion Starter #1
hey all, so i picked up this truck the other day :D. anyways i have been eyeballing this thing over the last year, chatting with the owner on and off. then out of the blue he calls me asking if i still want it, and its over at a shop as it died on him and hes tired of looking at it.

the truck is an 81 gmc, reg cab, short box 4x4, 1 ton axles, with a large 6cyl turbo diesel and a heavy cast iron 5 speed (bull low + 4 normal gears) manual trans behind it. that then has a custom adapter plate to mount a np205 transfer case behind it. now im having trouble identifying this engine/trans, it would be nice to get this figured out so i know what i have here.

this trans also has a really weird shift pattern, it looks like this
L 2 4
R 1 3

does anyone have any ideas? or any other place i should try asking?





















 

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I don't know anything about these, but I looked around. It seems that in the us, the 2 ton mitsubishi fusos back to the early 90's and maybe older are called FK and have "some big 6 cylinder". If it is a mitsi, I would bet that the trans is from the same truck (and that it has a 1:1 5th).
 

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Discussion Starter #5
yah its deff not the dodge mitsu (6dr45) as mine has the injection pump driven from the flywheel end. my engine is also substantially bigger than that one, i would say im 7-8L of displacement.
 

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I dont see why it couldnt be one though. Maybe yours is an industrial application with a rear gear train? The oil filter location and type is a dead give away though.

 

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Discussion Starter #8
no my oil filter housing is totally different, and i certainly have alot more than 100hp on tap. my exhaust manifold also was a factory turbo setup. they are not even close engines. my injectors are totally different, the intake goes in from the side, its from a 24v vehicle too.
 

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Looks to me like a 6D15, Google that model and look at some pictures, looks the same. They made several different displacements in the "6D1X" series of engines. Try looking for the model number of the engine on the front lower drivers side of the block, that is where it is on my 6DR5 in my 78 dodge pickup.
 

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. Maybe yours is an industrial application with a rear gear train?
no my oil filter housing is totally different, and i certainly have alot more than 100hp on tap. my exhaust manifold also was a factory turbo setup. they are not even close engines. my injectors are totally different, the intake goes in from the side, its from a 24v vehicle too.
Same family of engines just like 64 ford said. Dont be a corn cob.
 

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Discussion Starter #11
now the 6d15 is very close! im sure thats it. thanks for your help guys, heres some more pics to confirm













and heres my 24v vacuum pump (the power portion of the alt isnt even plugged in lol)



and my 24v starter







now the trans should be able to be figured out, as 4th gear has a broken or chipped tooth, it sounds like rod knock, but only in 4th (final) gear. they have also custom adapted a gm np205 transfer case behind it, which will make hooking the speedo back up nice and easy.



 

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Yeah there are defiantly only minor similarities with the 6DR5, that thing is huge! The valve cover is shaped the same but appears to be much larger. I hope you find the model number cast into the block somewhere, they may have not put it in the same place as the 6DR5.
 

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Discussion Starter #15
yes the 6d14 up to 6d17 are the same externally i believe, just ranging in displacement. the 6d15 does seem to be the most common tho, so ill go with that being it. this was also an NA engine, the turbo is on an elbow with 2 flanges, the one on a manifold being a simple 3 bolt exhaust flange and theres no way they put a turbo up to that factory.
 

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When you get it running, not doing yourself any favors pulling preheated intake air from inside the engine compartment. There should be room for an I'cooler in front of the water radiator, then get intake air from in front of engine compartment.

Ed
 

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Generally speaking, most trans' have direct straight back, and forward shift position gears are reduction of some sort. Most OD trans. In this country, have top (OD) in the forward position, some replaced 3rd gear w/ OD (NP, Clark, etc.) like in your trans. It might be OD in that forward position.

Ed
 
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