Opened the barn to find a small puddle of oil under the quad. Looked closer and it looks like its coming from around the drive shaft at the rear of the motor. There is a rubber boot on the drive shaft and it was filled with oil.

Anyone know where I can get a schematic of the motor and order the parts?

Anyone ever done a new seal? How involved? Anything else I should consider changing while its apart?

 

Lots of on-line parts suppliers, this is one 2004 Yamaha KODIAK 450 AUTO 4X4 (YFM45FAS) Middle Drive Gear | International Moto Parts
I did the seal on an earlier Big Bear and you had to remove the whole swinging arm assembly, then take off the angle drive unit and dismantle it, as the seal came out from the inside. However looking at the drawing, I guess remove the UJ spider, then the yoke, and you may get at the seal.

If the housing has to come off, you could need a new O ring, and having a new UJ spider assembly on hand, may be prudent.

 

Thank you Sir!! I think I will do a new rubber boot as well while it's apart

 

I think I have the same issue. How big of a job was it to fix?

 

You might want to pm him, that post is a year old.