So I have had this gen 2 since new. Newbie to the crawling/scale side of RC, this is my first one. I've had bashers throughout the years. So I took the rig out on my log/crawling course and noticed that the left rear wheel under load doesn't turn? Before I start taking the axle apart ( I've done this before for maintenance ) any ideas on what this could be so I can get parts on order lil. Thanks for any help in advance.