Castrol 10W-60 TWS

[Great White]

Originally Posted by Matt B

I just went though this threat as in our German forum we currently have a case of transmission failure and at the same time I'm tidying up my new Z.

My car, as mentioned before, is a 18.5kmls example and I strongly assume (but don't know for sure) that transmission fluid is still factory filled. There are two particular concerns in my case:
- avoid that the new oil removes old debris too aggressively leading to bulky particles that may clog oil passages
- make sure the thing will survive German Autobahn speed.

Castrol Edge 10W60 is fairly easy to get here, but as Marc Haibeck recommends Amsoil 5W30 I wonder which will work better or safer. Marc's recommendation seems much thinner and therefore sounds like improved lubrication at all temperatures.
I don't think either is wrong but is there any better or worse?

Not sure which is better or worse, but the thicker oils tend to quiet things in the gearbox a bit better at higher temperatures. My car has an aluminum aftermarket flywheel so things tend to get a bit noisy after they warm up on my particular blue tag. When I first bought the car, I filled it with Lucas Synthetic Stabilizer because I found nothing else available at the time. I have since switched to the Amsoil Synchromesh 5w30 and haven't had any issues. Both fluids have worked well but I was unsure of how suitable the Lucas would be in this particular application. (It survived a few rounds on the NCM MSP course with no failures with the Lucas stuff in there though.)