In order to answer complaints from arch competitor Trailways and other independent operators about being locked out from purchasing the PD-3751 model, GM simply took their existing 96" wide, 35' long suburban transit model, added more luggage bay space underneath, added sliding highway-style side windows, added reclining seating, and shortened the overhung portion of the front end by moving the front axle forward using a new front end from the wartime Yellow Coach "Victory Cruiser" model.

The easiest spotting features of a PD-4103 over the rare PD-4102 are that the later model included a rear luggage bay door on the left side that did not appear on either the PD-4101 or PD-4102, as well as an improved refrigeration system, using the same Ingersoll-Rand rotary vane compressor as previous models, but with a larger evaporator coil using a better expansion valve and a larger supply fan located over the rear passengers' seats.

This was given life due to a single (and often photographed) rebuilt PD-4101, owned by Colorado Southern/Burlington Trailways, that had suffered front end damage in a serious wreck.

In place of the exhaust fan grilles on the later model, the PD-4012 had a series of small holes punched into the sheet metal that made up the luggage rack soffit.

The PD-4104's ride and handling were far superior to that of the old steel sprung previous models, and paved the way for higher passenger and operator expectations all through the 1950s.

The new PD-4104 also was wrapped in GM's version of Raymond Loewy's "Highway Traveler" concept bus, which also shared most styling features with the later PD-4501 Scenicruiser, another exclusive Greyhound Lines model.

The PD-4104, although appearing to be completely new, actually was a heavy reworking of Greyhound Lines' previous PD-3751/PD-4151 models, as several structural members were identical.

Although made instantly obsolete by the new PD-4104 in 1953, the PD-4103 soldiered on in scheduled and charter service for another two decades, notably with Pacific Greyhound Lines in the San Francisco Bay area.

The many improved features and engineering of the PD-4104 and its modern, sleek appearance that matched its stablemate PD-4501 Scenicruiser, led ACF-Brill Corporation to exit the bus-building business in 1954.