My diff's has started to whine a little lately, around 50-60 mph, despite refreshing the fluid 20K ago. My previous W124 had the same issue. Am thinking to change the diff oil to 80W140 synthetic.
Anybody using this ??

THANKS!

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2011 Prius

I have it in my 126 gasser.



seems to be working. no noises and it still runs like a champ.

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-1983 VW Rabbit LS Diesel (5speed, VNT/Giles build)

Thanks. Is that the synthetic Red Line Oil stuff ?? Or perhaps Mobil or Castrol??

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2011 Prius