New Flyer produced 79 of these 1990 model buses for the TTC. They are similar looking on the exterior except the rear portion. But interior wise the are different through seating arrangement which is more cramped. This model also came with a number of firsts, the first TTC buses to be equipped with a Cummins L10 engine for the power to push the bus with the A/C unit intact. Those engines are very powerful, in divisions where they have operated from there have been complaints about the rattling these buses produce when they idle. The engine vibrates the a/c intake vent and the overhead a/c ducts where the advertisements are placed. This model was also the first to have the electronic Luminator destinations signs installed in them when delivered. As these buses run now they have been through the 6 year rebuild program and had their transmissions retrofitted as well as their rear wheel rims. In 1999 the TTC started to retrofit the ZF HP-500 4-speed transmissions with the Allison V730 3-speed. What they noticed is that due to the lack of the retarder which the Allison V730 does not have, the TTC should have retrofitted the transmissions with the Allison VR-731 which have these. You will notice that these buses now have low profile wheel rims and are painted white. The Commission has decided to retire these buses as they fail due to frame corrosion, the D40-90 fleet has been retired as of July 2004.