The problems with the Scenicruisers greatly soured relations between Greyhound and GMC. Greyhound continued to buy GMC coaches with the PD 4104 up through 1960 and the PD 4106 from 1961 to 1964. Given the problems with the PD 4501, Greyhound had no interest in asking GMC to produce a second version of its signature coach based on the PD 4106's mechanicals and styling. Greyhound also bought some PD 4107 buses from GMC which were known as the "Buffalo" model. Greyhound purchased 362 of these buses in two orders (162 in 1966 and 200 more in 1967, with the 1966 units being trouble prone). The company never bought another GMC coach afterwards. In 1958 The Greyhound Corporation acquired a controlling interest in Motor Coach Industries (MCI), Limited, of Canada and by 1961 had full ownership of it. This led to the end of its need for GMC coaches by 1968. GMC's sales soon went into terminal decline as both Greyhound and Trailways were building their own coaches.