What gearbox and diff oil to use?!? Please!!
 

I have a 2000 model impreza wagon sport (2litre awd non-turbo), the diff is clunky when warm. Going to do an oil change this weekend. What oil is best to use for the gearbox and rear diff?

Some people say 75/90, others say just 90. But is this for the gearbox or rear diff or both?

Thanks!!

castrol syntrax 75/90