Thelma purchased from Hall a used truck that had been manufactured by International Harvester. In order to work on the truck engine, it was necessary to raise the cab of the truck. When it was so raised the cab fell unexpectedly and fatally injured Thelma. Suit was brought for her wrongful death against Hall and International Harvester. The suit was based on theories of negligence, strict tort, and breach of warranty. The defense was raised that there was no liability because the sale to Thelma had been made "as is" and the truck was a used truck. Were these defenses valid