Trans oil - hope I ordered correctly - please verify - 986 Forum - The Community for Porsche Boxster & Cayman Owners

husker boxster · 02-23-2018, 04:33 PM

Hi WMJosiah,
Interesting info. Does your data base have any info on Motorcraft Synthetic 75w-90?
Thanks.

wmjosiah · 02-24-2018, 04:20 AM

I'm just looking up spec sheets on the web - I don't have any special sources. The spec sheet for that oil you just mentioned says:

Viscosity at 104F: 76.0
Viscosity at 212F: 15.4
Viscosity index: 211

Thanks for mentioning this - that actually looks even closer to Porsche Spec than the Lubri-Moly GL-5... but it's GL-4, not GL-5, which many people on the web claim is a good thing in these transmissions because apparently GL-5 can wear copper bits, and our transmissions have those?

Have you used the Motorcraft Synthetic 75w-90?

I'm sure there are other specs that are also important and I know very little about oil.

husker boxster · 02-24-2018, 04:43 AM

The Motorcraft lube is coursing thru the veins of my CSS. On day 3 of my Indy DE last Aug, I started to have issues with the 3-2 downshift. It could be crunchy at times. It was my original trans fluid. Got home and started researching the flushing process and fluid options. Heard the Motorcraft was good, so I tried it. Fixed the crunchy downshift, but is a bit stiff until warm on winter days.

My CSS had 53K mi when I did the change, including 4-5 DE weekends per yr over 5 yrs. The viscosity of what came out was extremely thin, even compared to what was going back in.