Mobil1 75w-90 vs brandx 75w-85

[oil pan 4]

Amsoil and Redline has it.

Amsoil site has an interesting and excellent base for the specs on the 75w110..........which is currently in my daughters Tahoe.........from what I understand, the 90wt of today is on a different scale than in the past........
@Pablo can elaborate on the subject.

It was probably thicker when it was dino oil.

 

[Pablo]

Amsoil and Redline has it.

Amsoil site has an interesting and excellent base for the specs on the 75w110..........which is currently in my daughters Tahoe.........from what I understand, the 90wt of today is on a different scale than in the past........
@Pablo can elaborate on the subject.

https://www.amsoil.com/p/amsoil-severe-gear-75w-110-100-synthetic-gear-lube-svt/?zo=515729

Basically (now years ago) SAE split the old SAE Gear oil range 90 into the new 90 and the new 110 ranges.

I find it comical there are so many old images of the old chart still on the interwebs

And so few NEW compliant charts:

 

[Pablo]

For the record I checked.

2005!

SAE 110 was added as part of the revision to the SAE J306 standard in 2005

https://www.sae.org/standards/content/j306_200506/

 

[oil pan 4]

For the record I checked.

2005!

SAE 110 was added as part of the revision to the SAE J306 standard in 2005

https://www.sae.org/standards/content/j306_200506/

Makes sense because 90w is covering about 12 to 21is cSt. And most of not all the 140w oils I've seen tests for all lived on the thicker end of the 140w scale.