75w85 Syn. or 75w90 semi syn
 

I'm looking to do a relatively cost effective oil change, however I'm not sure which way I should go.

I've got a couple of options but can't seem to find any which match up with the specs (without spending a fortune on Motul)

There is a 75w90 semi synthetic from Penrite which is GL-4/GL-5 compatible or numerous 75w85 full synthetic GL-4 oils.

Should I use the 75w85 full syn or the 75w90 semi syn?

I currently have Nulon 75w85 full syn GL-4 oil in the transmission and it seems to do OK. Will be changing the oil again as I track the car a fair bit so figure a transmission oil change per year will help keep the gearbox in good condition.

While I often don't knock on people for saving money and not always going with the "Best" or buying some knockoff parts etc.

If you're concerned about spending $45 dollars for Motul or any other top quality gear oil that you shouldent have to change for a few years, maybe you should really think about about what it is you're wanting out of a vehicle.

The OP is in Australia and would pay about $45 per liter for Motul.

http://bikeshop.com.au/collections/o...motul-gear-300

OP, IMO you'd be fine with a 75W-90 semi-syn at the track. PenRite Trans Gear is even thicker than Motul Gear 300 at 100C. I also don't think you'd gain anything by changing the gear oil out earlier than recommended.

-Dennis

Thanks for your replies.

As above, Motul Gear 300 is about $45 a litre here vs around $15 for the other options. Penrite also comes in a 2.5ltr container so the difference between a Motul gear oil change and a Penrite is about $95 (as I have to buy 3ltrs of Motul). Australia - The land of double the price.

Doing around 8-10 track days a year I think changing the gear oil out more regularly will help to keep the gearbox in better condition than it would otherwise be in. Leaving it in for the full duration would worry me.