Okay, so today I drained Mobil 1 75W90 out of my gearbox and replaced it with Redline 75W90NS. (There has been a debate as to whether synthetic oil is good for Sube transmissions at all, under the thread name "Rear diff oil")

 

Having only done about 6 miles with the new oil, I can't make any final conclusions but there is a slightly more soft/damped sensation to the way the gearstick slots home. Also, the whirring noise I had on the overrun in third has dissappeared, which speaks highly for the film strength of Redline.

 

The difference in shiftability is only slight, at this stage, but I expect that anyone making the change from a mineral oil to synthetic would be very impressed by Redline NS.

 

I have been through Castrol and Mobil, both mineral and synthetic, so I reckon I have experience enough to make a fair judgement.

 

 

Pianodirt, I would recommend forking out the extra money for Redline. You won't be disappointed.

 

Sprintman, my gearbox has 185K miles on it, so age shouldn't be important.

 

Cobb Tuning only recommend one oil for any Subaru, trans, diff etc. Redline. Mainly a Group V basestock (PE) and a high quality additive package. If you think its expensive in NA it's double that here (Oz). Pays for itself in time though with reduced fuel consumption (up to 6%). And where did this syn oil isnt good for Subes come from? My Sube dealer offers syn for regular servicing and I checked with Subaru Australia who said "it all helps". "Just dont change from factory fill until 12,500kms at least".

Don't look at me, I didn't start the anti-syn movement

Agreed

GL wagon, D/R4WD 5spd. Has always had a 'notchy' shifter (hasn't gotten any worse in 75,000 miles. Not hard to shift, just can feel it (maybe just needs linkage adjust?). No tranny or differential leaks or noises. If it even MIGHT smooth out the shifting it would be worth it. Now, the engine I'm disinclined with 205,000 miles unopened.

If your handbook recommends GL5, then I would say yes! It's not quite a new-gearbox-in-bottle or anything, but it will certainly improve the shift.

 

Bear in mind that Subarus have always had a notchy 2nd to 3rd shift.

 

Not savvy on the older Subes: Do you have direct rod link to the 'box? Cables tend to mask notchiness, while a rod allows you to feel every synchro tooth mesh into the cogs, just the way I like it

I run Redline SuperHeavyweight Shockproof in my gearbox and diff...

 

absolutely love the stuff.

nobody's gonna convince me to swap to anything else.

 

Redline all the way.

 

jamie

I checked my OM and it does take GL5, it looks like one gallon will do both the tranny and the diffy. I'll do it this weekend. Prolly needs changing anyhow, it's been about 50K.

A gallon should see you through. The capacity listed in the manual is for a dry gearbox. Since it is impossible to drain all the old out, I only fill 3.2 litres in my 3.5 litre 'box - and it always hits the full mark spot on!

(I use the excess to "flush" the box before filling.)

 

SubieGal, have you tried NS? Can you "compare and contrast" NS and Shockproof?

 

Shift speed, cold performance, that sort of thing..

Subie Gal & gang: Where did you get this redline stuff? Y'all 'bout got me convinced!

Quick crossbolt, join the club!

 

http://www.redlineoil.com

Remember it's two different oils for trans and diff. Do not use 75W90NS in the diff.