In 1996 Oshawa Transit purchased five used 1981 General Motors T8H-5308A buses from Denver Regional Transit and assigned them bus numbers 146 thru 150. The Denver Regional Transit buses were distinct, aside from their higher bus numbers on older GMC buses within Oshawa Transit's fleet, in that they had the retrofitted air conditioning unit on the roof when they were purchased whereas the Oshawa Transit GMC buses of the same make did not. The newly acquired Denver Regional Transit buses also lacked a small window between the front doors and the first opening passenger window. This might have been due to the needed reinforcement of the body structure to hold the extra weight of the Air Conditioning units on the roof.