Alright. The K5 is running. Almost everything has been fixed. Exceptions are the speedometer (shredded both gears in the T-case). It's the 41/15 Yellow/Grey gear combination, and the speedo was dead on with this ratio. Still not sure how that's possible, given the regearing.

But I don't feel like pulling the T-case apart. And if I've run out of desire to fix it, now is a great time to sell it (no, I'm still not looking forward to it).
Also haven't fixed the E-brake (which I never intended to fix), backup lights, or the cracked mirror. Other stuff all works.
Next step is writing up an advert. So far I have not been any good at selling vehicles, so I'll take whatever input you guys have. I think I'll throw it on Ebay first for crazy money to see if it gets any bites. And then post a real ad up after that goes nowhere. I like the Detroit, and I don't think it adds much to the resale value, so I've been planning on pulling that out for the next project. Same for the $100 Tinytach (I'd just put the old voltmeter back in that hole).
Here are my rough thoughts on what an ad should look like. Too wordy?
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1986 Chevrolet M1009 (D10 Military Blazer)
Odometer reads 47,000 miles
6.2L diesel engine
NV4500 manual transmission
NP208 transfer case
3.73 axle gears
GM 3/4-ton 10-bolt front axle with Eaton Posi.
GM 1-ton 14-bolt full floating rear axle with Detroit Locker.
Previous owners claimed to have completely rebuilt both axles. I changed fluid in both axles and added the Detroit to the back. E-brake cable is missing.
5-speed NV4500 manual transmission swap completed in late 2016. At that time I also installed:
* All new clutch hydraulics.
* All new shocks.
* Rear main seal.
* New glow plugs, rewired to run off of 12V instead of 24V (24V system is otherwise stock).
I have been daily driving it since then.
Other mods include:
* Manual glow plug switch (previous owner).
* Electric fuel lift pump.
* Dual voltmeter (independently measures 12V and 24V systems).
* TinyTach diesel tachometer. I was going to keep this for my next project, but the speedometer gear shredded recently and I have run out of time to fix it.
* Tires are 245/75R16 on newer 8-lug rims. 75% tread.
* Driver seat & front seat belts taken from a newer truck. I'll include the matching passenger seat (split bench) if desired.
* Rear window has been converted to a liftgate from a pickup topper.
* Bluetooth/USB/AUX/FM stereo.
* Adjustable proportioning valve to set the ratio between front and rear brakes.
The truck is eligible for Military Vehicle plates, but has a clear (civilian) title in my name.