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Did a bit of a general service last week doing oils, filters etc and changed the gearbox oil while i was at it. i put in some Castrol 85w90 and a tube of Nulon G70. (said it was OK for passenger car and light duty 4WD transmissions)

Well all i can say is I want my filthy black muck that came out back in the box! I will admit that I did no research on what oil to get and just read the bottle and it seemed like a good fit, so i probably made a mistake. Ive always had a bit of a crunch sometimes changing back from 3rd to 2nd but now it happens every time without fail and feels much harder to get into gear. In general the gearbox feels smoother mostly but it definitely worse on that downshift.

so what are you guys out there using, im going to dump this new oil first chance I get and put something else in.

Well subaru specify a transmission oil (GL-5) suitable for combined diff/gearbox ASSYs such as L'series which employ hypoid gears. Suggest you use Multitrax or similar designed for such combined transmissions (Approx 3.3Litres for part time 4WD box).
Using the straight gear oil probably is the source of the symptons.
As for the G70 treatment, I am currently using it no prob. I believe a number of forum members have used it too - with no adverse results.

J

I am about to (some time soon) give my L box a dose of G70 hoping to fix a crunch from fourth to thirth - if I brake a little on down shift - no crunch. Often find self going for 2nd instead

I've been using Penrite Synthetics all around and Neways Roil additives with great results.That's all been in EJ engines all round though. The 04 Outback will get the treatment when I get a moment.

Personally I don't use any additives but I do change my oils a lot sooner than recommended. I use Castrol VMX80 oil and find it works extremely well on hard to shift gears but due to it's lower grade, I change it every 2 years.

I think my synchros really need some abrasive rub down

I find, that if I use my clutch properly there seems to be much less metal particles accumulated on the gearbox drain plug:rolleyes:
That said you would have to let a gearbox go for a long time before the oil came out black:!:

Well I got some Castrol Multitrax oil which is recommended for Subaru 'hypoid' transmissions.

There is a definite improvement! Im basically back to where I was before the oil change in terms of that crunch between 3rd > 2nd but its waaaay nicer now and sometimes doesnt crunch at all It certainly behaves better when its warmed up too.

As a warning to others, dont get Castrol 'Manual' gear oil for your L Series, mine hated it.

Glad to hear it's working better. I've used Multitrax a few times then changed to VMX and never looked back.

I'm also worries about these additives that make the oil 'cling' better, you know the one that supposed to hang onto the gears? I'm always worried that this clinging effect will also hold onto metal, thus allowing it to work it's way back onto the gears and create more wear

I could never get my head around stuff like Slick 50 and if it makes everything slipperier (reads more slippery ) how is the friction need by synchros gonna not slip and go CRUNCH! I don't think I have changed gearbox oil in any of my subes except when I get them, or fit another box
Paul, is Castrols VMX80 cheaper coz it is cruder ?

Might have to get some before I add G70

I just use whatever the Penrite LSD oil is - goes well and doesn't over heat when the going gets tough. This oil is what my trusted local parts joint recommended me.

My only issue with this oil is the usual cold running "stiffness" of the gearbox - but I've always had that with other subaru gearboxes too

Simply by changing my gearbox oil I had a much better feel in the gearbox shifting etc - that was when I didn't know the age or history of the gearbox oil.

Cheers

Bennie

I used Penrite SinGear 75 (75W90 - full synthetic), found it helped a little but I think my synchros are simply worn

From Castrols site - VMX80

Mild extreme pressure gear oil with special viscosity stabilisers to overcome shift problems. Recommended for use in transaxles of most front wheel drive vehicles with a transverse engine and manual transmissions experiencing low temperature shift problems. SAE 75W/80, API GL4.

A 4 litre pack retails about 45 bucks and seen on the friendly sca website

dearer by the litre bottles @ ~ 14 bucks

Try it out one time Jonno.. when you have one that is a bit tricky to shift. I was put onto it by an old Subaru gearbox rebuilder and I've never looked back. I know it's hard to tell others.. it's more try for yourself and see.