if you definitely know it is selecting gears sounds like you have a clutch problem,the clutch cable may be badly stretched and out of adjustment.if you have an oil seal leak the clutch fibre linings can be contaminated and clutch slips with no vehicle motion.clutch may be worn out part or of it brocken,some vehicles have a cover plate on the bellhousing you can remove to see part of the clutch system.
xs11
April 2010