Not that thick in the Audi A3 TDI DSG transmission. The Audi-VW DSG transmission in the A3 uses spec G 052 182 A2, which has a kv100 6.8, which puts it close to the thin Dexron VI & Mercon LV spec, also close to Nissan Matic S too. I hope you didn't use 75w-90 GL-5 in the DSG by mistake.denwood wrote: ↑Sun Apr 25, 2021 11:13 amFrankly I was surprised that the final drive oil was so thin on the LEAF as I'm quite accustomed to 75w oil being used in differentials on most cars I've worked on. These ICE diffs operate at far lower RPMs, so it's obviously the EV motor drive RPM that is dictating the use of highly engineered fluids. The Audi A3 TDI that I serviced recently had some pretty interesting 75W fluid used both for final drive and DSG trans operation. It also took a laptop and $700 of software to service correctly....249 ft/lbs of torque from that engine at 1200 RPM. So again, it's a bit weird to be putting such low viscosity fluid in what is essentially a differential.
Nissan Matic S - Kinematic Viscosity @ 100°C cSt ASTM D445 5.2
Typical 75w-90 Gear Oil - Kinematic Viscosity @ 100°C cSt ASTM D445 14.56
https://pim.liqui-moly.de/pidoc/P000247 ... 2.0-us.pdf
The Audi A3 rear differential does use a typical 75w-90 high-viscosity GL-5 gear oil, high-visc & GL-5 due to a Hypoid gear with a lot of sliding friction as it turns rotation 90 degrees. The Leaf doesn't turn rotation vectors 90 degrees at all & hence doesn't need 75w-90 GL-5. ...
Our Leaf's gears & differential are all helical involutes, not Hypoid, and therefore don't use high-visc GL-5 stuff.
A good starting point for understanding why a Leaf gearbox wears more at low-speeds & high torque loads, read the summary below:
https://www.motioncontroltips.com/why-i ... brication/