2008 Mule 3010 diesel burping oil out the front final drive vent. Oil smells like 80-90 gear oil. Found information that it should be 10W-40 oil. Drained and installed 10W-40 and burping stopped. Another site said 80-90 gear oil. Unit has about 250 hours. Not sure which is correct.

 

I do not know. There has to be a manual on your ride somewhere for free, but here is a low fee one. 2005 to 2008 Kawasaki Mule 3010 Full Service Manual

Good Luck and welcome to KF