Two names: chassis and body
The chassis is everything under the body: frame, engine, steering, brakes and wheels. Freightliner's MT45 and MT55 and Ford's F-59 are common walk-in van chassis. The body is the aluminum walk-in box built on top, by a body company such as Utilimaster or Morgan Olson.
A listing like “MT55 · P1200” gives you both: the chassis model, then the body model. [1][2]
What P700, P1000 and P1200 mean
The P number is the body model name. In dealer listings it rises with body size: an 18 ft Utilimaster walk-in is listed as a P1000, on both a Ford F-59 and a Freightliner MT45, and a 20 ft body as a P1100. P700 bodies show up on the lighter Ford E-450, and P1200 on larger builds.
It's a model name, not a measurement, and lengths vary by builder and spec. Confirm the actual body length, interior height and width on the unit's spec sheet before you plan a layout. [3][4][5]
| Body | Seen as | Chassis |
|---|---|---|
| P700 | Smaller walk-in body | Ford E-450 |
| P1000 | 18 ft walk-in | Ford F-59, Freightliner MT45 |
| P1100 | 20 ft walk-in | Ford F-59 |
| P1200 | Larger walk-in body; check the spec sheet | Freightliner MT55, Ford F-59 |
Length, height and width
On the Freightliner MT45 and MT55, Morgan Olson offers its walk-in body in 18, 20, 22 and 24 ft lengths, with 85 in of interior height and about 93 in between the wall studs.
Utilimaster's walk-in bodies are listed with a choice of two heights (81 or 85 in) and two widths (93.5 or 96 in). The taller body matters when people stand and work inside all day: kitchens, coffee bars, retail, clinics and command posts. The wider one leaves more aisle with equipment on both walls.
For a sense of volume: one dealer lists 14, 16 and 18 ft walk-in bodies at 740, 850 and 960 cubic feet. [6][3][2]
MT45 vs. MT55
The two Freightliner walk-in chassis differ mainly in how much weight they're rated to carry. Morgan Olson's spec sheet lists the MT45 at 14,140 to 19,500 lb GVWR and the MT55 at 20,500 to 30,000 lb. Freightliner rates the MT55 for bodies over 1,500 cubic feet, on wheelbases from 158 to 300 in.
In federal weight classes, that puts the MT45 in Class 4 or 5 and the MT55 in Class 6 or 7. A 2026 MT45 with a gas engine and an 18 ft P1000 body, for example, is listed as Class 5 (16,001 to 19,500 lb).
Both are offered with a Cummins 6.7L diesel or a GM 6.6L gas engine. Heavy builds, with generators, battery banks, cooking equipment, cabinetry or water tanks, are where the MT55's higher rating earns its keep. [6][7][8][4][9]
| Spec | MT45 | MT55 |
|---|---|---|
| GVWR | 14,140–19,500 lb | 20,500–30,000 lb |
| Weight class | Class 4–5 | Class 6–7 |
| Engines | GM 6.6L gas or Cummins 6.7L diesel | GM 6.6L gas or Cummins 6.7L diesel |
Weight rating and the CDL
Under federal rules, a single vehicle with a GVWR of 26,001 lb or more is a Group B vehicle and needs a commercial driver's license. MT45s sit well under that line. An MT55 can be rated either side of it, so check the rating on the specific unit if your drivers don't hold a CDL. [10][6]
How to choose a size
Start from the work, not the truck:
- List the stations and equipment: cook line, espresso bar, workbench, workstations or shelving.
- Count the people working inside at once and the aisle they need.
- Add storage, water and power equipment, then estimate the loaded weight against the chassis rating.
- Check where it has to park and turn: events, streets, docks or job sites.
- Pick the shortest body that fits the layout with room to work, on a chassis rated for the loaded weight.