Small Engines (Lawn Mowers, etc.): honda hr214 approx. 16 yrs old rear drive lawnmower, honda hr214, gear teeth

Question
I have never had a problem with this machine.  Recently I put on new front tires and rear pull over treads.  Now, when I engage the drive (rear drive), the mower makes a clicking sound and tries to engage the drive, but will not do so until I push the mower forward a little (with the blade clutch on so the blade is spinning).  When I engage the drive with the blade off (not spinning), the drive usually engages smoothly, although sometimes it doesn't and makes the clicking/trying to engage.  What should I look for as the problem?  Thank you.

Answer
A clicking sound from the drive usually indicates the gear teeth are worn and jumping over each other rather than engaging.  Remove the rear tire assemblies and do a visual inspection.  If the gear teeth are OK, it's likely the driveshaft bushings are worn and allowing the pinion gears to disengage.  Hope this helps.