I have a 2001 Polaris TrailBoss 325 that recently started to make a clanking noise in the transmission. It only happens in reverse, but the forward gear is fine. What is going on in the transmission for this to happen?

Also what transmission fluid should I use in it?

 

Most of the time it's usually a stretched silent chain jumping teeth making the noise,but since reverse is gear to gear and not driven by the chain itself,could be anything from worn engagement dogs on the slider gear,a shift fork problem,or a gear itself. Still wouldn't rule out a silent chain causing the noise though. Only sure way to know is to pull the gear case and tear it down. Not that hard,just harder to get it out of the frame than it is splitting one. What ever you find wrong ALWAYS replace the silent chain and seals as the chain does take a huge amount of wear and gets slack over the years. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse A cheap manual would also help,plus it does have good pics/instructions on repairing the gear case internals in case you get into trouble. Here's a 2002 manual,but same gear case and just about everything else is the same as the 2001 except decals.2002 Polaris Trail Boss 325 Service Manual PDF Download Polaris AGL for the gear case or any oil that says suitable for chain driven gear cases. PLUS check that the drive sprocket isn't worn down or its internal splines worn or a worn drive chain that could be causing the noise. Would be a lot simpler to repair if that's the problem..

 

Thank you very much this has helped I will look into it