\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?
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.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)