Cosmo Kramer

Hello all

Just did some maintenance on the weekend and changed out my gearbox oil. I think I still had the OEM Porsche fluid in there, I have only 50,000 miles on the car but I felt it was time. Man are the fill and drain plugs ever tight, I broke my 10 mm Allen socket on the fill plug! Ended up using a straight 10 mm Allan key with a jack handle as a cheater.

Anyway, to those who are looking for a good replacement fluid for the OEM Porsche stuff, give it a try. Gear noise is reduced and shifting is so smooth now. I used to use Motul ester based oils in my sportbikes and had the same result.

I ended up buying from an online retailer that specializes in motorcycle parts, 3L shipped with taxes was $81, it is probably cheaper for those in the USA. It is GL4/5 approved so it meets the requirements for our boxes.

http://www.motul.com/system/product_...%29%5B1%5D.pdf

Nedster

Was your shifting noticeably harder when cold, and did that change with Motul. Mine are pretty notchy when cold, had replaced it with new OEM fluid but didn't change anything.

Cosmo Kramer

Mine was notchy when cold too but today ambiant is in the high 70's so hard to judge. It is smoother on cold startup at these temps then it was before. When we have a cold day I will report back and give my impression.

GTgears

The factory service interval is a joke. Change your gear oil every 15,000 miles or every 2nd year, whichever comes first. You'll thank me when you don't need to rebuild your gearbox until after 100k mi instead of at 60k or 70k.

Cosmo Kramer

Have a couple hundred miles on it now and all I can was is wow, I can't believe how much smoother it is, warm, cold doesn't matter. I have a short shifter as well so any notchyness in the box is very apparent.

Highly recommend guys!

Rapewta

I changed the manual transmission gear oil at 75K.
I think Porsche sugggests a change at 90K.
Anyway, I used Mobil 1 Synthetic 75W-90 LS.
If anything, it runs quieter and shifts eaiser. Can't really notice a difference.
Have over 88K now so far so good.

D6lc

I changed at 42k to the Porsche recommended, and I struggle to notice any improvement.

Can you use the Motul on cars with an LSD?

Cosmo Kramer

They have Gear 300 LS for limited slip boxes, but the viscosity specs are much different. Maybe an additive could be added to the regular stuff?

Gear 300: http://www.motul.com/system/product_...%29%5B1%5D.pdf

Gear 300 LS: http://www.motul.com/system/product_...pdf?1303841962

KrazyK

Not trying to be harsh but do you realize this is not the right gear oil? The OEM Porsche gear oil is like night and day compared to the Mobil stuff. It may be a little more but its worth the difference in how much better the trans operates, cold, warm, doesnt matter. Dont know whats in the stuff but it works better than any after market brand.

Cosmo Kramer

The Motul I put in was better then the OEM Porsche fluid that was in there, but again it was old with 50,000 miles on it. I referred to this chart when I decided, Motul was on the only one that had cold and hot viscosity specs that surpassed the OEM Porsche fluid (Shell), plus I could get it very easily.

morganabowen

I am getting ready to change the fluids in my tranny, and with 131K on the odo, this may be the way to go. You used Motul Gear 300 75W-90 How much does it use?? Is there a filter

yank_my_chain

Is there a difference in the gear oil from Porsche for a tranny with LSD?

dennis hiip

I also referred to above chart and went with Liqui-Moly. Shifts great

Luxter

That's soooo cool, people use my chart!!!


Heard stories that Motul Gear 300 would cause G-box to whine....

Cosmo Kramer

Yes 75w90, no filter, tranny uses 2.7 liters. The plugs in the transmission are mega tight. Take out the filler plug first!