986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - 2nd gear, hard to shift after tranny oil change

Smallblock454 · 02-25-2015, 09:20 AM

Hi Gelbster,

whoa. Dynamic viscosity is really hard to explain for me, because english is not my mother tongue and this is a complex physics topic.

The wrong viscosity can harm much more than using the wrong oil. Cinematic viscosity decribes the viscosity to density ratio. It is measured in mm²/s. You use a Viskosimeter (don't know the english term) to measure it.

Please check Viscosity - Wikipedia, the free encyclopedia for a detailled desription. Think that can explain it better than i can do.

And yes, the difference between 81 vs. 115 is a lot. I think that can cause not only a bad shifting but also damage to the transmission.

Also dynamic viscosity is very different. 35.000 vs. 135.000. That means S6 AXME is 4 times viscous / thicker than S5 ATE. And that will harm the transmission definitively.

So Shell Spirax S5 ATE 75W-90 or Mobil MOBILUBE PTX 75W-90 are the right oils.

Regards from germany
Markus

02-25-2015, 09:20 AM	#28
Smallblock454 Registered User Join Date: Jun 2014 Location: LB, Germany Posts: 1,456	Hi Gelbster, whoa. Dynamic viscosity is really hard to explain for me, because english is not my mother tongue and this is a complex physics topic. The wrong viscosity can harm much more than using the wrong oil. Cinematic viscosity decribes the viscosity to density ratio. It is measured in mm²/s. You use a Viskosimeter (don't know the english term) to measure it. Please check Viscosity - Wikipedia, the free encyclopedia for a detailled desription. Think that can explain it better than i can do. And yes, the difference between 81 vs. 115 is a lot. I think that can cause not only a bad shifting but also damage to the transmission. Also dynamic viscosity is very different. 35.000 vs. 135.000. That means S6 AXME is 4 times viscous / thicker than S5 ATE. And that will harm the transmission definitively. So Shell Spirax S5 ATE 75W-90 or Mobil MOBILUBE PTX 75W-90 are the right oils. Regards from germany Markus Last edited by Smallblock454; 02-25-2015 at 10:15 AM.