Originally Posted by antarius

In California, PC 496 is possession of stolen property. The law states that you have to have "reasonably known, or known" that the property was stolen.

When you purchased the vehicle, which otherwise checked out as legal, you could argue that it's not "reasonable" to check the serial numbers of transmissions on vehicles that are otherwise legal.

In California you wouldn't (most likely) be held responsible for it, though in some cases I'm sure people had charges of PC 496 brought against them, requiring them to defend themselves.

You could very easily check if it's stolen by grabbing the serial number of the transmission, contacting the Police Department of your choosing, or the one the person mentioned specifically, and tell them you want to make sure your transmission wasn't stolen, and if it was you'd like to press charges on the person who sold it to you.

They can run a check in APS (Automated Property System) and determine whether or not the property is stolen. If it is, you'll have to purchase yourself a new transmission, but because you took the initiative of bringing it up to the Police Department, they'd be unlikely to charge you with possession of stolen property as it shows that you clearly didn't know if it was, or was not, stolen.

The right thing to do is to contact your PD, or that other PD, and check the serial number on the transmission. From there you can take the appropriate actions, whether that be returning it to the original rightful owner (sucks for you, but it's the right path to take), or responding to the AIM kid and saying "haha fuck off you liar" if it comes back clear.

In general though, you wouldn't be held liable. And "HPD auto theft Sergeant" sounds like total crap to me.