"But when I picked the car up from them it had another 600km on the speedo than it did when I dropped it off", he alleged.
While Timmerman denied any wrongdoing, Mosley claimed he also discovered his car had been driven at speeds of up to 170km/h with an aftermarket GPS system showing it had been driven to Rotorua and back twice.
"It looks like they took it for a joyride, obviously because they liked the car," he said.
Timmerman responded by saying he had hired a lawyer to demand Mosley pay $58,000 in unpaid bills as a result of Power Torque's work on the car and to threaten defamation action over Facebook posts.
Now he says the dispute with Mosley is what drove his business under.
He told Stuff today that Mosley's unpaid bills and defamatory comments on social media had caused Power Torque to lose more than $300,000 in other work as a result of the bad publicity.
The collapse of the business also left local employees out of a job and hurt Taupo schools that been sponsored by Power Torque, he said.
"If Mosley had paid his bill we wouldn't be having this conversation," Timmerman said.
Mosley, in turn, told the media outlet he had no sympathy for his former mechanic but did have empathy for the small businesses that would never be paid money owed them by Power Torque.