Hi !
I have my Suzuki for 5 years now and never changed differential oil .Car is 2001 and have 84500 miles
I Checked in user mauel it said that oil should be replaced at 7500 miles and after that just regulary inspected . If oil must be replaced should car be in level or rear must be lifted to fit more oil . We had a lot snow this year in New Jersey I used 4WD couple times and it is running good .
Thank you for your help