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Looking for recommendations for best manual transmission oil to use for 2006 NC 6-speed to give smooth gear changes, particularly when cold. Or any experience with additives to achieve smoother gear changes? It's also been suggested to use auto transmission fluid - any ideas please?

malyou wrote:Looking for recommendations for best manual transmission oil to use for 2006 NC 6-speed to give smooth gear changes, particularly when cold. Or any experience with additives to achieve smoother gear changes? It's also been suggested to use auto transmission fluid - any ideas please?

My NC had a slightly crunchy 2nd gear. I used the factory spec gearbox oil and no probs since. I’d try that first before anything else.

Thanks for that, I'll give it a try. My NC also has a slightly crunchy 2nd gear. Pedal stroke and free play both in spec.

I'm using Nulon GL4 oil for my gearbox, smoothest shifts I've ever had

Thanks. I've since identified that my car currently has the factory spec oil which is a GL5 oil. Like what you've done (suggested by other forums as well) I'm about to try a GL4 oil which by many reports 'fixes' the problem.

malyou wrote:Thanks. I've since identified that my car currently has the factory spec oil which is a GL5 oil. Like what you've done (suggested by other forums as well) I'm about to try a GL4 oil which by many reports 'fixes' the problem.

Just double check as I thought factory spec was GL4 in gearbox and GL5 in the diff? Whichever way round it is, don’t put diff oil in the gearbox regardless of what people on t’internet say!

The problem can be merely a driver ramming the gearstick through the gate without any feeling for the gearbox or previous owners who have abused the gearbox and worn the synchros. The owners manual lists the specs and provides other useful information.

Tried Red Line RED50304 MT-90 75W/90 GL-4 Manual Trans Gear Oil. Done 2,000 km since. Gear change much improved but reconciled to fact it will never be silky smooth like NA I drove for 15 years.