I changed my front diff fluid out to the amsoil front diff fluid today and was coming off a hill in adc to see how my 1000 would react to the new fluid and heard a loud clunk from the front diff and sounded like something had broke so I took back home and drained the fluid and didn't see any chunks or shavings so filled it back up with amsoil and took off another hill and again a loud clunk two times so I took it back home dumped the amsoil and put polaris demand drive fluid back in it and all is well again no clunking adc working as it should and my 1000 did not like the amsoil and just wanted to pass it along and not bashing the amsoil my atv just didn't like it and just wanted to pass it along to prevent a diff failure