April 20th, 2010.
M35A2:
I believe a few of the members here have answered your questions, perhaps better then I can. The Air Shift uses an independent air cylinder to pull in the front axle clutch, and a resturn spring incorpiorated in the unit releases the clutch when the air is exhausted. A switch in the cab which combines an air valve and an electric contact is under the drivers control. When thrown to the "IN" position, air is admitted to the slave cylinder to engage the front axle, and a light turns on by the switch to tell the driver that it is engaged.
When thrown to the "Out" position (the lever, that is) the air is vented to the atmosphere, the front axle disengages, and the light goes out and the truck is in 6X4 or only the rear axles driven.
The modification to air shift should be as a fairly simple kit, and I shall have to crawl around under my truck to see where it is situated, but it should be doable without a machine shop or machinist involved. As to the mirror, you should have no problem acquiring a new set of west coasts, or take offs, and I doubt that they are strategically significant enough to prevent them being exported. Eastern Surplus should be able to help you with the air shift and the mirrors if you can find them nowhere else. The older trucks started out with the Sprague clutch system and the small round mirrors, but as others have said, these trucks have been almost continously adapted over their lifetimes to perform many different missions and to fill many different needs.
My truck "Saddam's Nightmare", has the air shift, west coasts, and springer seat applied to it in rebuild, I have added the Air-O-Matic steering out of deference to my shoulders and age, and also the TACOM push button headlight switch system. It will likely get a cab heater shortly, something which it has never had, but which is needed now and then even here in Texas. The name was bestowed for her service in the First Gulf War of 1990, but she served in Vietnam also.
I can see where the BEdford would be missed, and I bet the gents with the really big Scammells are going to be hurt by the inspection requirements, too. Good luck on your truck, and do refer to me, if you can, as Kyle, as we aren't overly formal around here....
NB: Regarding the photos of the dashboard, the Alt seems to be in the yellow, could be low engine speed or loose drive belts,Normally it should be in the green band. As to the temperature guage, when the temperature is up, the temperature guage should run about 169-189*F, roughly, but it takes some time for these engines to warm up at low speeds or low ambient temperatures. We usually use a winter front, or front end cover, when it gets below the 40*F range, to help the diesel stay warm one just regulates the flap on the winter front to control air flow to the radiator.