Transmissions have cooling lines that go to a radiator for cooling, but would have to be "poked" fairly hard. I know a fair amount about the scientific testing done in crime labs, and it's something that is next to impossible to beat. It's not worth lying because science will tell the truth eventually. With that being said, it is scientifically impossible for T.H. to have been killed inside of S.A.'s trailer, or garage. The scientists themselves couldn't rid a structure of all of someone's DNA after being shot and stabbed.... or shot.... or stabbed.... or whatever version of the story one choices to believe. It's simply not possible.