What's with HYPOY-C

[Jason Scoville]

I'm having trouble finding this 80 90 gear lube HYPOY-C. Can anyone tell me what the difference is between the GL-5 and HYPOY-C? And where do I find it? And really how necessary is it?

[Andyman]

I thought hypoy-c was an additive in GL-5 for certain non syncro transmissions.

Check the fine print on the back of GL-5 bottle maybe .

[Rock Doctor]

GL-5 is EP Gear Oil

Hypoy-C is Castrols product name for Non-Synthetic EP Gear Oil.
Syntrax is Castrols product name for Synthetic EP Gear Oil

I think

RD