I am keen to change this at my next service which is due, which is the best spec/make to use??

I do mainly fast road, and some trackdays as I only use it at the weekends.

Cheers

Logan
MY95WRX

 

Castrol Syntrax is recommended or any good semi-synthetic 75W-90 gear oils; Red Line, Valvoline, Motul etc will do the job. You will need 4 litres. Gear box takes about 3.7 litres.

 

Don't use Redline 75W90NS, it noticeably reduced the effectiveness of the synchros. i.e. made it more crunchy on changes, on my 2000MY. Official Subaru oil (Shell) is better, lots of people have recommended Castrol Syntrax, I haven't tried it myself,.. maybe I should, as a last ditch attempt to stop that bloody crunching into 4th !

 

Cheers for the advice. So semi-synthetic is better than fully synthetic??

 

Use Motul GEAR 300, works great in MY03 WRX

 

I had crunching into 4th, got the gearbox oil changed (and a quickshift as it was all free fitting). No probs now and the box has had a serious run out

Rup

 

Yep, fully synthetic oil is usually too thin for scooby gearboxes and may cause gear grinding or selection difficulty, especially from cold. Most manufacturers produce both fully synthetic and semi (or blended) oil in 75W-90 grade. Worth reading the label and getting a good quality semi-synthetic as mentioned previously.

 

Castrol B373 is very very good.