Thread: Penrite Sin Manual Trans 75/85 Vs Castrol Syntrans

Originally Posted by rick130

Most modern GL5 fluids are buffered so are safe for yellow metals, but....

The extra treatment rate of EP additives in GL5 oils over and above GL4 oils can impact on synchro function unless the right FM's are used to enhance synchro performance.

Oils like Motul Gear 300, Castrol Syntrax Universal work fine in synchro 'boxes, and I'm guessing Penrite have done the same with Pro Gear 75W-90 but I have no experience with it.

Will report back in a few months. Penrite Pro Gear 75W-90 going into the MT82, t'fer box, and both (ATB equipped) diffs tomorrow.

Originally Posted by komaterpillar

what are your initial impressions since the change? in particular with shift quality and synchro action?


will be doing a driveline service on mine in the next week or 2 and still deciding between Penrite and Motul.

Ok so it's been 3 weeks and 1500km since the Penrite ProGear 75W-90 was put into my gearbox. (...and diffs and t'fer case).

I had no real issues with shift quality or synchro action before moving to the Penrite oil. Same afterwards. Apologies I can't offer much more insight than that - my bum-dyno just not sensitive enough to pick up much in the way of change.