Mvez

OK, any of you 987.1 6spd owners running a Giken LSD? If so, what gear oil are you using? The amount of conflicting info with regards to what oil should be used is comical.

Before anybody says, get a Guard, I know, I had one in my .1RS, loved it, but I got my hands on the Giken for next to nothing, so going to try it. However, their units seems to "operate" somewhat differently than other clutch type units. Seems the thicker oil viscoity is more critical to the Giken operating more smoothly. We've proven this in our miatas (use only Giken 80W250).....so trying to balance good LSD operation with properly lubricating the 987 gearbox.

I've read Motul Competition Gear 75W140 (contains LS additive) is what Giken recommends for transaxles. However, you don't see many recommending that weight for any Cayman 6spd gearbox, even if it includes the LS additive. Some do though, because the gearbox gets so hot, but say the LS additive isn't necessary, which makes sense to me.

Seems like most gearbox companies will say use 75W90 no matter what.

I previously used Millers Oil 75W90 NT (non-LS) in my .1RS and it was outstanding. Thinking I would just try that and see how it works, as I know that weight is good for the Cayman.

Input appreciated.

Mvez

lol, lack of input proves my point.

I guess I'll report my findings. I think I'm going to try a gear oil near the middle of the 90 and 140, which is the Miller's Oil 75W110 NT. Gearbox builders like 90, Giken says 140....this seems like a great compromise, with no LS additive.

box986

Putting in a OSG LSD in my 997.1 manual soon, should I use OSG oil or Porsche 75W90?

Mvez

Do not use os giken gear oil

85Gold

I had a OS in my 6GT2 and ran Syngear II 80/140 with no issues beyond being a little notchy on the 1 to 2 shift on cold mornings. Also ran it in my 04 GT3 after that with no problems and when warm shifted much better than the OEM fluid.

Peter

wellcoached

From OS GIKEN re my 986 boxster S Diff:

For Porsche applications we’ve had great success using Motul Gear Competition FF 75W140.

garrett376

Not sure it helps your question, but I've used 75w-90 Motul 300LS in my 02 996 for many years (almost 8) and it's great with no notchy shifting, no noise.

Mvez

Yeah, giken told us about motul as well, but I've been running the millers crx 75w110 non LS since this post with good results. Diff locks like a champ, and if I ever decide I want it less aggressive I can switch to 140 weight or use an LS version.

I don't have a trans cooler so it gets nuclear, which s why I'm not concerned about friction modifier.

Had a friend who used the motul and said it's fine too. I think either is fine.

garrett376

I don't have a cooler either, and mine is a club racing car.

Oh dear... I just noticed you posted your original question over a year ago. Oops...

Mvez

The giken works a bit different than say a guard unit, but typically they will say stay away from LS additive for racing and hardcore track use because it gets too slippery from heat. I'd say try LS and non LS and see which one u like better. But I would def use 110 or 140.

jdistefa

Like you, have been using Millers 75w90-NT. With a Guard. No useful opinion/experience re. Giken.

But with a Cayman I'd say get a tranny cooler otherwise you're gonna shake and bake yer unit.

jrgordonsenior

Synolec 75-140 w/o friction modifiers...
http://products.lelubricants.com/Asset/9920.pdf