What is the difference between gear oil or fluid and manual transmission oil or fluid for Subaru WRX?

What is the difference between gear oil or fluid and manual transmission oil or fluid for 2002 Subaru WRX Sedan Manual 2.0L?





And what type (gear or manual transmission) oil or fluid should I use?


I was told 75W90 or 75W90NS, but I really don't know which one to use for the manual transmission. Like when I'm in 2nd, 3rd, and 4th gear and let go of the gas pedal, I hear it rattling underneath and a mechanic told me perhaps change the gear/manual transmission oil or fluid?





Also, what oil or fluid should I use for the rear differential (LSD)?





Thanks.What is the difference between gear oil or fluid and manual transmission oil or fluid for Subaru WRX?
Search the forums below. I use synthetic 75W90 in my trans and rear diff...no issues.





The rattling sounds more like a loose heat shield or exhaust.What is the difference between gear oil or fluid and manual transmission oil or fluid for Subaru WRX?
Take out the rear seat and listen to that noise you are hearing. If it is from the back, rear diff has too much play. If it is up front, front diff has too much play. Fluid will only make a sound difference if you are severely low on it, and I bet you would see the puddle.
If you're not sure, take it in to the dealer for the service. I believe 75W 90 or 75w90NS would do just fine if you going to DIY.