Problem with rear hub Leitner Berlin Cruiser
 

Hello. The rear hub drive on my Leitner Berlin Cruiser is grinding - the motor seems to be turning OK but its not turning the wheel. It sounds like something has come loose inside. It happened on a hard uphill. Any thoughts? Thanks

Looks like it has a geared rear hub motor (read ebikesca), so possibly there's a broken gear. Only way that I know to discern is open the hub. Ask your dealer; if parts are available, the repair could be fairly straightforward.

Thanks for that hopefully it is a simple part replacement and not the whole hub

In order to reduce noise, many geared hubs have thermoplastic gears which can fail if they get too hot or are exposed to high stress. Normally easily replaceable with the most challenging aspect getting to them. Maybe look up on YouTube.

Hmmm that sounds right - the hub was a bit noisy from when I bought the bike secondhand a few months ago, so it might have been on its last legs. Hopefully a clean up/replacement of gears will see a noise reduction

The type of lube is important too, so check on that too.