Spec B 6sp Manual - correct oil?

[Anson]

Gday ladies & gents

Planning to change to oil in my gearbox.
3rd into 4th gear is starting to crunch after hard driving and the oil heating up.
Hoping its just the oil losing its properties and not the synchro...

Reading through the form people are recommending the redline stuff, but reports of the oil gunking up...
Next is the Castrol syntrax 75W-90 full synthetic. But unsure if it the Longlife?, Universal Plus? or Transaxle & Manual Transmission Fluid?, which are all 75W-90
Cant find the Longlife in shop anywhere, but can find the Universal Plus and Transaxle & Manual Transmission Fluid...

Any other recommendations?

Cheers, Anson

[Brunsy3.0]

i use Penrite for everything, gear changes are still smooth after approx 20,000 so far, plenty more changed to be made, i believe it was 75w90 transgear i used

each for their own though

[cliffo3rb]

Give the syntrax manual a go first.

I had the same problem in my 6mt a years ago and went with the Redline oil which fixed the problem.Have since done over 150k (30k intervals) with no dramas, even with alot of abuse.

[Anson]

Thanks Daniel, will give the Penrite a look...

Cheers Cliffo, which redline product are you using?
Heavy Shockproof?
Lightweight shockproof?
MT-90 75W90 GL-4 Gear Oil?

[cliffo3rb]

Lightweight shockproof.

Alot of people say not to use it as it clogs up the gearbox. I tend to agree, but at the time I had nothing to loose so I gave it a shot.

[sheppo9]

Alot of people say not to use it as it clogs up the gearbox.

Only clogs up if/when you change to another fluid and don't flush it properly.

[owen]

Motul Gear300 75w90 would probably be the best oil you can put in your gearbox and diffs

[HardwareBoB]

I put in
Castrol Syntrax Universal Plus 75W-90 today, and it seems to work, $30 from supercheap
Note: this replaces Castrol Manual Syntrax 75W-90

[Anson]

Have ended up buying some Motul Gear 300 for the gear box and Motul P90 for the rear diff...
Finger crossed Motul fixes the problem. If not, than will try Redline.
Have narrowed down the gear crunching problem a bit more. It seems when I drive the car from cold
the gear box is fine, but if I park up somewhere for a bit, than start driving again, it will crunch going into 4th gear.
So hopefully its just the case of the oil soaking up the heat from engine and losing its viscosity.

[owen]

You need gear300 for the diff as well. PA90 is mineral, straight 90 viscosity

[SubMeister]

I've hit the regular service interval for the 6MT trans oil and front/rear diff oil change. My car has no issues.

I called Subaru and tried to order the oil they use. They parts guy said they don't have a Subaru branded oil for the 6MT and diffs. They just use Castrol Universal 80/90.

Are you sure, I asked. So he went over to the service dept and came back saying they have Castrol Universal in 200 litre drums, and there's a sticker on it that says it's approved by Subaru.

Go figure, I thought they'd use some special formulation for the 6MT. The Motul sounds tempting though...

[sheppo9]

They parts guy said they don't have a Subaru branded oil for the 6MT and diffs.

He/his manager can't be arsed to stock it and they get it cheaper (or make more money more like it) buying the 44's from Castrol.
Part number is SAS1099, retail $92.28 for a 5L.
A rip off, and 99% sure it's just Syntrax with a subaru sticker on it.