All, How often do you change the 'differential' oil and what type/brand of oil?How do you know/feel that it hasn't been changed? (What the heck is 'differential' anyways?) Thanks.
better get the correct weightage plus the correct oil... if u wanna go for redline or any other type of oils. getting it wrong may results in your final drive going kaput-o!
Yes, pls get the correct oil... the standard "open differential" will do well with a wide range of manual gearbox oil, so long as it's within the viscosity range recommended by the car manufacturer... but if you have LSD (limited slip differential) pls be very careful with the type of differential oil...
Non-LSD and manual gearbox can use Redline MT90, it's a 75W-90 viscosity, fully synthetic.
If LSD make sure the word "LSD" is printed big big on the oil pack... not sure which Redline oil to use, since I don't have any experience with LSD, yet.