I didn't know synthetic oil was bad for my transmission. I just changed the oil to synthetic. Should i change it again?

Synthetic is ok. Just make sure it is NOT GL-5 gear formula with sulfur.

Thanks Blue. Its not GL-5. Its castrol synthetic gear oil.

Thanks Blue. Its not GL-5. Its castrol synthetic gear oil.

As long as it's not Castrol 'Syntec' gear oil. That is GL-5. I have part of a container that was left over from working on my daughter in law's Lincoln LS. On the label it says 'Fully synthetic, API GL-5 and MT-1, SAE 75W-90 formula'.

I will look for the bottle. If I cant find it I will change it again to make sure. I love my old Z. Thanks foir the input. It will say G-L5 on the bottle or should I look for something else on the lable?

It says it on the back.

Thank you very much. I don't have the bottle so looks like an oil change (again)

I also use Redline MT90 (75w90) which is of the GL4 specification.

Synth fluid for the z tranny is good as it protects better. Not all trannys appreciate synth, however (ie: wrx)