In 2021, after a long competition, the USPS announced it had awarded a $6 billion contract to Oshkosh Defense to produce the Next Generation Delivery Vehicle, which will replace the LLV.

[7] The Grumman LLV was the first vehicle specifically designed for the United States Postal Service (USPS); the USPS provided a specification and three teams created prototypes that were tested in Laredo, Texas, in 1985: Grumman in partnership with General Motors, Poveco (a joint venture of Fruehauf and General Automotive Corporation), and American Motors Corporation.

Prototypes were each subjected to a 24,000 mi (39,000 km) road test, including frequent starts and stops, gravel surfaces, cobblestones and potholes, hauling a payload of up to 2,000 lb (910 kg).

[8] Previously, Grumman had built a limited number of KurbWatts, a battery electric vehicle with an aluminum delivery van body, which was tested by the USPS in the early 1980s.

[9] At about the same time, Grumman also built 500 KubVans, which used a similar lightweight aluminum delivery body on a Volkswagen Pickup diesel chassis and also underwent testing by the USPS.

[citation needed] Like the older postal-service Jeep DJ-5, the Grumman LLV features a right-hand-drive (RHD) configuration, in contrast to the typical left-hand-drive (LHD) position of vehicles in North America.

This arrangement positions the driver on the side of the vehicle closest to the curb, enabling the carrier to easily grab sorted mail and place it into mailboxes without having to leave the seat.

[11] The body and final assembly is by Grumman, and the chassis is made by General Motors, based on the 1982 Chevrolet S-10 Blazer, powered by GM engines including the 2.5-liter inline-four TBI Iron Duke and, in later production, 2.2-liter inline-four SPFI LN2; the instrument cluster and front suspension are similar to those used in the Chevrolet S-10 pickup and S-10 Blazer sport utility vehicle.

The vehicle was tested successfully in warmer climates, but when used in places with substantial snowfall, they became difficult to control and were poorly adapted to those conditions.

[23][24] The CLLV was essentially the same as the LLV, with the same chassis, built by GM at Moraine Assembly using S-10 components, driven by the 2.5L Iron Duke through a 3-speed automatic transmission and a 7-5⁄8" positraction rear differential with 3.42:1 final drive ratio.

[28] The Solectria/Grumman LLV was equipped with a 12-kilowatt-hour (43 MJ) lead-acid traction battery and 5-kilowatt (17,000 BTU/h) diesel-fired heater, giving it a nominal range of 30 km (19 mi).

The ECRV uses a 90-horsepower (91 PS; 67 kW) AC induction traction motor driving the rear wheels, drawing power from a 2,000 lb (910 kg) lead-acid battery consisting of 39 modules at 8 volts each, connected in series.

Each second-generation eLLV was converted by a different group, funded by the USPS through a $50,000 grant to each electromodder, and tested in Washington, D.C.[26] In the nine-month period from March to December 2011, the five vehicles had taken an aggregated 9,181 trips and traveled a total distance of 3,965 miles (6,381 km), consuming an average of 0.645 kW⋅h/mi (52.3 mpg‑e) of AC power (from the wall).

[17]: 2–2 The LLVs also suffer from several design deficiencies, including inadequate cabin climate controls (no air conditioning and a heater prone to breaking down).

The wheels and suspension are not suited for the all-terrain and all-weather needs of delivering mail and require snow chains during inclement weather.

[40] According to documents obtained in 2020 via a Freedom of Information Act request as part of a Vice Media investigation, 407 LLVs have been damaged or destroyed since May 2014.

[43] The Office of Inspector General found that the Postal Service's acquisition plan for replacements lacked details and while the USPS could continue deliveries until 2017, there were concerns over the aging vehicles.

[46] On September 22, 2016, the United States Postal Service awarded the NGDV Prototype Contract to six selected suppliers: AM General, Karsan, Mahindra, Oshkosh, Utilimaster, and a joint-venture bid involving Workhorse and VT Hackney.

The prototypes would represent a variety of vehicle sizes and drive configurations, in addition to advanced power trains and a range of hybrid technologies.