Neither snow nor rain nor heat nor gloom of night stayed this courier from the swift completion of its appointed rounds. Note the "Sonic Eagle" USPS logos on the doors; this became the official USPS logo in 1993, nearly a decade after the final Jeep DJ-5s were built. Plenty of these trucks stayed in service into our current century, and a few are still being used by private mail-delivery contractors in rural areas.
During the American Motors era of Jeep DJ production (1970 through 1984), a bewildering assortment of engines went into postal Jeeps. This is a 2.5-liter GM Iron Duke four-cylinder; before that, DJ-5s came with Audi power (more or less the same engine used in the Porsche 924, in fact), AMC straight-sixes, and Chevy Nova four-cylinders. The 1984 DJ-5Ms ran the AMC 2.5-liter four-cylinder.
The earliest DJs were equipped with three-speed manual transmissions, but the American Motors-built postal-delivery versions all had automatic transmissions. This one has a three-speed Chrysler Torqueflite A904, a weird engine/transmission combination that should help you stump your friends during car-trivia debates. Check out the ultra-bare-bones heater/ventilation controls!
These trucks were badged as AM Generals, not Jeeps (I couldn't find a single Jeep label anywhere on this one), just like the original HMMWV. However, you'd have to be a real hair-splitter to refer to this as an AM General DJ-5 instead of just Mail Jeep or Jeep DJ-5.
Next time you complain about your subcompact rental car lacking driver-comfort features, consider this vehicle.
I had a few high-school friends who owned DJ-5s, back in the early 1980s when they were available for a couple hundred bucks at government-surplus auctions. The first thing civilian DJ-5 owners always did was tear out the mail-sorting table and replace it with a random junkyard bucket seat (or an aluminum lawn chair). These trucks were very noisy, very bouncy, and very slow, but they always ran.