Where to find a complete power train CAD?

Hi all,

I am looking for some files and hope that someone could help me find them.

Basically a complete power train and drive train in 3D format. So engine, transmission, differentials and axles. Preferably all from the same car. But separate models could also do. STEP preferably.

Some models here are alright but when it comes to the inner components, parts are missing. Like piston rings, main bearings, etc. Small but important details. Other models have these details but are only a model of a small sub assembly. So maybe a crank-piston assembly has all the details, but is missing the rest of the engine. That's why I think an actual model of a power train would be great. I hope you understand the problem for me.

If anyone knows a good place to download or buy these models, I would be very glad.