75W80 vs 75W90 gearbox oil

DutchV40 · Sep 5th, 2007, 08:20

What is the exact difference between those oils?

Is 75W90 a little bit thicker when warm compared to 75W80?

75W90 is advised to suppres singing noises of the gearbox...

Liberty555 · Sep 5th, 2007, 08:36

Hi DutchV40

The short answer is 'Yes'.

But, because one oil says 75W90, it does not mean it has exactly the same viscosity as another with the same rating - it means it is within a specified range, determined by SAE or ASME or whoever. In other words, a good quality 75W80 could offer better protection, noise supression etc, film strength and so on than a 75W90, plus, lower viscosity can mean better efficicency.

As they say - 'Oils 'aint Oils'

Sep 5th, 2007, 08:20	#1
DutchV40 Senior Member Last Online: Apr 5th, 2011 12:21 Join Date: May 2007 Location: Brabant	75W80 vs 75W90 gearbox oil What is the exact difference between those oils? Is 75W90 a little bit thicker when warm compared to 75W80? 75W90 is advised to suppres singing noises of the gearbox...

Sep 5th, 2007, 08:36	#2
Liberty555 Member Last Online: Aug 20th, 2009 08:27 Join Date: Jun 2007 Location: Limerick	Hi DutchV40 The short answer is 'Yes'. But, because one oil says 75W90, it does not mean it has exactly the same viscosity as another with the same rating - it means it is within a specified range, determined by SAE or ASME or whoever. In other words, a good quality 75W80 could offer better protection, noise supression etc, film strength and so on than a 75W90, plus, lower viscosity can mean better efficicency. As they say - 'Oils 'aint Oils'

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