Auto Tranmission Fluids!

[Kesh]

Hey guys, done a bit of research and searching around the forums and am seeing a lot of mixed info with regards to what fluids to use.

I believe Castrol Transmax Multivehicle is a good choice for the 5 speed autos? The differentials are confusing me though, is the only specification required GL-5? In that case, is Penrite 75-90 Pro gear oil good for both the front and rear diffs? I'm curious to hear what you're all running.

Cheers for your input!

[HardwareBoB]

Yes, 75W90 fully synthetic, I'm using castrol syntrax now, but using nulon performance smooth shift when I do my 6MT change because it's a bit cheaper

[Kesh]

Cheers for that!!

[sprite798]

one of subaru mechanic told me rear diff should use " LSD " oil and subi use castrol LSX90

but not for front diff and gear box,

so my question is , castrol syntrax & penrite pro gear 75-90, are they LSD oil? do you guys use them for both rear diff and gear box?

[HardwareBoB]

subaru front diff (and gearbox on manual cars) and rear diffs all use the same specification of 75W90 gear oil. AIUI Subaru will use normal castrol 75W90 and STi wil use syntrax 75W90.

viscous LSDs have a special fluid that makes them a 'limited' slip diff, however this is internal to the diff, and not a service item. They use normal gear oil for the gears.

[BillyCorgi]

^2
As above.
Early model Limited Slip Differentials used conical clutches that were in contact with the lubrication oil.
These LSD units required different oil as "normal" gear oil would ruin the friction qualities of the conical clutch and render the LSD effect NUL.

Subaru rear differentials which are "limited slip" use either sealed viscous couplings or the Gleason Power Systems Torsen differential.
Both of these use normal GL-5 lubricants.

[sprite798]

Thanks guys

at end I chose Penrite ProGear 75w90 for gear box (manual & front diff) and Castrol Axle LSX90 for rear diff.

gear box shifting smoother than before evidently