Ok I'm thinking of changing my tranny oil and diff oil in my next service. Unfortunately I will not be able to get my hands on the brands that you guys have over there. I was looking around and found some Castrol Hypoy 90, its SAE 90 API GL-5. From searching the forum, I guess this would work for the differential but what's that "hypoy" mean? Does that mean I can't use this for the tranny? The castrol website doesn't say its synthetic or not.

If I use SAE 90 in the tranny, does it mean it will just be harder to shift when cold but still all right (no harm to tranny).

Sorry about these questions.

Hypoy mean hypoyd gear cut. the way the gears are shaped. For your tranny it might be too thick if the temp. go down a lot. Try to get synthetic one o lot more fluid.

The gear shape is "hypoid", much quieter, but the pinion gear makes a "sliding" contact with the crown gear, needs special extreme pressure oil.

GL5 is made for this service. Don't use it in the gearbox unless it states it is OK for service "GL4" (different additives).

S

Ok I bought some Kaaz Powertrain Gear Oil GL-5 80W90 which I was told is synthetic but wasn't, I'm too lazy to return it so is it ok to use it on both tranny and diff.

Bump:

Guys help me out here, I only have 3 days to decide whether I use these or return to the shop I bought from. Thanks

That 90 weight Castrol will be fine in the rear diff. Does it say GL5/GL4, or just GL5?

Don't put GL5 in the tranny.

S

If it's not synthetic, I'd return it.

Is there a reason you cannot purchase Royal Purple or Redline from say Europe and have it shipped?

That's not Castrol, I bought some Kaaz, its GL-5 80W90, would it work?

I live in Asia so its too much trouble getting from Europe, the freight charges will cost somewhere as the oil.

bump::

Looks like this needs ONE more try -

1 - It will be OK in the differential.

2 - Unless it says "GL4 compatible" DO NOT PUT IT IN THE GEARBOX.



(Now go ahead and put it in anyway, you seem very determined. :banghead: )

S

Looks like this needs ONE more try -

1 - It will be OK in the differential.

2 - Unless it says "GL4 compatible" DO NOT PUT IT IN THE GEARBOX.



(Now go ahead and put it in anyway, you seem very determined. :banghead: )

S

Sorry I anger you man, the manual says the tranny is compatible with GL-5, I went to my dealer and they showed me the stuff they normally use for the 8 and its also GL-5 90 from Helix. That's why I had to verify so many times, sorry dude.