https://en.wikipedia.org/wiki/Grumman_LLV

Even as simple as it was, the LLV was a major departure from the Jeep DJ-S, which was just a modified right hand drive Jeep CJ-5 with a sliding side door. In both cases the off the shelf parts available directly from the manufacturers extended the service of first two official USPS mail trucks well beyond their intended lives. Something which is unlikely with Oshkosh given the heavily custom nature of it. Refits to the LLV have included buying drop-in replacement LED headlights to replace the original square sealed beams since the form factor is a standardized part shared across the entire automotive industry from the 1970s onwards. Meanwhile the headlight assemblies for the NGDV are custom made, from the shrouds to the LED driver boards (an expensive problem shared with most headlights these days). We may have a similar problem to the Cadillac XLR's taillights where the driver boards make it infeasible to replace them.

These are things like: giant unpainted bumpers, sliding drivers door, the rear door has to be roll-up rather than normal doors, step through from front to rear, some size requirements.

One of the alternatives which was rejected when they signed the contract for the new vans was a customised Ford Transit.

> Domestic auto production is defined as all autos assembled in the U.S.

45k-60k units would be a 1/5th or 1/6th of all domestic production in the US for a year.

Contract stipulates between 5k to 16.5k units per year, with a production run for a ten years, which means parts, repairs and overalls are going for another 10-15 years after the run. It's a quarter century investment, if not more - the last LLV was made in 1994:

>> The lifespan specified by the U.S. Postal Service was 24 years, but in 2009 this was extended to 30 years. The majority of LLVs have been on the road for over 27 years.