1973camarolt

iTrader: (1)

I just had my open diff plate welded at PBM and I'm deciding on an oil to pour into it. The car is used 50/50 between street and drift miles. I'm looking for an oil that will happily survive the high temps found in a Z33 diff while lubricating the ring and pinion well. Being as it's not an LSD, friction modifiers are irrelevant. This means I want an open diff fluid. Very few people drive open diff Z's on tracks etc. so it's hard to find a well-tested open diff oil.

I see that Redline makes a 75W90NS gear oil, which is the same as the 75W90, but with no friction modifiers. In my searches I found many people liked Motul 300 as well.

What would you recommend? Bonus points for opinions from people who run welded diffs.

dcains

iTrader: (15)

Any GL5 spec 75w90 will be fine. Good luck with a welded diff on the street, though.

dkmura

iTrader: (64)

I used to run a welded R200 diff in my GT5 Nissan racecar. I found a synthetic 75-90W handled the high heat better than a conventional oil. In my case, Valvoline 75-90W synthetic worked well (particularly as they were a sponsor) and I would swap it out every other race.

1973camarolt

iTrader: (1)

Sweet, thanks for your responses guys. Is GT5 a road racing class? What sanctioning body is it under?

dcains

iTrader: (15)

SCCA runs GT5:

http://www.na-motorsports.com/Organi...ing/Rules.html

dkmura

iTrader: (64)

Yes- GT5 was a small-bore sedan class that transitioned to GT Lights (GTL) several tears ago. I currently run T3 in a 350Z, but don't use a welded diff in that class.

1973camarolt

iTrader: (1)

That's really cool. I bet you're a very good driver after racing momentum cars for so long.