Recently came up on the forum that ir you use synthetic engine oil in the Grizzly/Kodiak with the Ultramatic transmission that it causes the one way output bearing to leak.

Can anyone vouch for the validity of this. . .preferably with personal experience? Has anyone used synthetic and had this leakage problem or used synthetic and not had this problem?

We just bought an '01 Grizzly and Kodiak. . .both 4x4 w/the Ultramatic transmission and they have both had synthetic oil in them for the past 7 years and there was no sign of leakage anywhere on either quad. . .1200 & 800 miles on each respectively. . .but like I said in a recent thread a Yamaha tech had told one of the forum members not to use synthetic in the Ultramatic trans and the tech hadn't given the member any reason not to trust him in the past.

Thanks guys!!!

 

We use synthetic oil in all of our off road toys. In the Grizzly's we use Motul 5w40 double ester synthetic oil. In the Rhino and Raptor we use Motul 10w40 double ester synthetic oil. And in the KTM bike we use Motorex 10w50 double ester synthetic. We've never had an oil leak of any kind, including the one way bearing in our Yamaha ultramatic transmissions. And we've used synthetic oil in a total of 8 Yamaha's with ultramatic transmissions in the last 10 years.

The one way bearing doesn't leak, it isn't a gasket or a seal, it is a bearing.

Synthetics are fine to use in the ultramatic transmission as long as they do not have friction modifiers. Friction modifiers may make oil too slippery and cause the wet clutch in the ultramatic transmission, or any manual transmission sport quad or motorcycle to slip. But friction modifiers can be found in both synthetic oil and regular oil, so just avoiding synthetic oil isn't the answer. You need to read what it says on the bottle of oil you are using, and if it says it has friction modifiers in it, don't use it. If it says "ATV Specific" or "Motorcycle Specific" that also means it is safe to use with a wet clutch. Although the bottle doesn't need to say ATV Specific to use it in an ATV.

 

DesertViper,

thanks for sharing your experience. . .I prefer synthetic myself so I will continue to use it. . .

The bearing leaking didn't make sense to me, but I figured I would rather hear from people with personal experience with synthetics than just go with what someone told someone else.