I was going to get some fully synthetic gear oil but i've noticed on previuos threads that semi is better. I can get valvoline semi- 75w/90 gear oil cheap, is this a good enough oil? Has anyone else used it? Or should i go for castrol syntrax instead? Also i noticed the castrol syntrax was syntrax universal, is this the right stuff?

 

Syntrax is now labelled Driveline. This would be my fluid of choice but Valvoline is fine. Valvoline are a large, long established American Co.
Get Syntrax direct from Castrol on www.castrolclassicoils.co.uk Much cheaper than from Halfords!!
JohnD

 

The Valvoline is good stuff; easy changes from cold. I switched from Syntrax in my 5 Type R about a month ago on a recommendation from a local motorsport dealer who uses it. It is much better value at £5 to £5.50 a litre. Get the 75W-90LS blended (good also for the rear diff).

 

Cheers blindside, i take it thats the semi synthetic then? For some reason valvoline recommend the fully synthetic

 

Yep semi-synthetic or 'blended'. Fully synthetic is too thin for most scooby gearboxes

 

I've seen it said before that fully synthetic is too thin for scooby boxes, but surely if they are all 75/90 then they are all the same viscosity, and therefore by definition the same '' Thinness '' they might however be more '' Slippy '' ( great these technical terms aren't they) and of course every manufacturer will have his own friction modifiers, and aditives, hence the difference in suitability to scooby boxes. Thanks for the tip on price, JohnD, I was just about to head off to Halfords !