GEarbox oil GL4 vs GL5?

[the godfather]

So, just trying to buy some 75W90 gear oil for my box. I cant seem to get any GL-4. Seems only GL5 is available. Now apparently GL-5 will destroy my syncro's.
Is this true?
And where do I get some GL-4 in Perth hills area?
and can I use GL-5 until then?

THE GODFATHER.

[Ben-e-boy]

I dont know too much about the GL codes.
I use castrol VMX80 for its anti friction addative. its available in most auto parts store
Cheers
Benny

[TuffTD42]

GL5 is high in sulphur additives which is not kind to yellow metals. do not use GL5 where GL4 is recommended.

X2 on the castrol VMX80, it's good stuff.

[big_fletch]

Gday godfather, yes I've also been told not to use GL5 in place of GL4 box oil in my'01 42TD due to the softer metals. Got no idea if this is true but I trusted my source. I think I got mine (Castrol VMX-M GL4) at Supercheap but cant be 100% on that with my goldfish memory and all. I remember I had to hunt for it a bit.

I run the same oil as you Plassy, works a treat and i also run some nulon g70 gearbox treatment as well beacuse i have worn syncro's.. Box is smooth and quiet :smiley_thumbs_up:

[TuffTD42]

x2 on the nulon G70.