I would say the trucks or bogies are driven from forward wheel up to forward wheel slightly down (relative to the airplane longitudinal axis).
Here is what it looks like: a 'gear swing' of the main landing gear of a 777 (-300ER) in the hangar.
Only the two ACMP's (electric pumps) are used, this is why the gear retracts very slowly.
https://youtu.be/b93ekEpTZ-w
Another one:
https://youtu.be/w4bTPq6qNTs?t=24s
On a 777-200:
https://youtu.be/NYyWdbTWtSs
In the air: truck attitude during retraction:
http://cdn.c.photoshelter.com/img-ge...akeoff-09R.jpg