The General Motors PD-4106 was a 38 or 45 passenger Parlor series coach built from 1960 to 1965 in the United States. It featured larger side windows and a different front and rear design then the PD-4104. A 8V71 engine allowed the A/C system to run off of it instead of a separate motor. 
3,226 were built in total. The PD-4106 introduced many significant improvements,  powerful rear mounted GM diesel engine, air conditioning, air suspension, tinted windows, large underfloor luggage capacity, restroom, a new increased length to 35 feet and incredible durability and reliability. GM built 3,226 PD-4106’s at GM Truck and Coach in Pontiac, Michigan, USA with 43 destined for Australia, 35 new and 8 ex Greyhound USA. The GM PD-4106 is powered by a GM V8 2 stroke diesel engine, 568ci model 8V71, transversely rear mounted, with a 4 speed Spicer angle drive constant mesh transmission. The model designation PD-4106 stands for P - Parlour Coach, D - Diesel, 41 - 41 seats and the series, and 06 - the sixth model in the 41 seat series.