Straight 90W GL-5

[vettenuts]

The front hubs in my Workhorse chassis require a straight 90W GL-5 gear lubricant. There aren't many left on the market and I can't find any locally. Shaeffer's makes several but in all honesty it is totally confusing they have so many. It was recommended that a synthetic not be used due to seal issues but I haven't been able to verify that in writing with Workhorse. I have also found the Motul PA-90 on line, which is a straight 90W.

Looking for recommendations on lubricants that will meet my specific requirements.

 

[dparm]

Much like modern engine oils, the basestocks are getting so good that "straight" weights are actually classifying as multi-grade.

I think a 75w90 GL5 would work just fine.

 

[Ken2]

Does it actually require a GL-5 gear oil?...those are for hypoid gear sets. If not, an industrial gear oil would work. ISO 220 viscosity is the same as 90 wt, or AGMA #5--all the same viscosity. You might find an industrial supplier who'd have a gallon for sale.

 

[NHGUY]

Amalie makes 80w90 GL5,and Parts Plus 80w90 is Amalie (on the east coast).

 

[vettenuts]

Originally Posted By: Ken2
Does it actually require a GL-5 gear oil?...those are for hypoid gear sets. If not, an industrial gear oil would work. ISO 220 viscosity is the same as 90 wt, or AGMA #5--all the same viscosity. You might find an industrial supplier who'd have a gallon for sale.


Yes, it is very specific that the requirement is GL-5 straight 90W. There is no mention of being able to use a multi-weight.

 

[MolaKule]

Schaeffer's #209A in 90 weight should work fine.

Schaeffer Oil #209A

I would just go purchase a 75W90 or 80W90 hypoid gear lube or something like this:

Gear Oils

BTW, are you aware most 75W90's are a 1 cSt thicker than most 80W90's?

That 90 weight requirement must be because the manf. and dealers sell that lube for $20.00/qt.

 

[Pablo]

Searching for a straight 90 goes against most all of BITOG learning.

If I had an app that required SAE 90, I would use 75W-110 to assure I got the upper end of the OLD J306 90 100°C Vis chart.

 

[artificialist]

Most Japanese cars used SAE90 in rear differentials and transfer cases, but I never had any problem replacing it with 80w90 conventional or 75w90 synthetic. If you have to have a SAE90 GL-5, you might be able to get it at a car dealership. Mitsubishi Dia-Queen 90 meets that spec.

NAPA has a gear oil that might technically meet OEM specs. They have an oil labeled 80 85 90 GL5 for that purpose: http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Gear-Oil-Automotive/_/R-NO_75210_0006411584

 

[salesrep]

Originally Posted By: Pablo
Searching for a straight 90 goes against most all of BITOG learning.

If I had an app that required SAE 90, I would use 75W-110 to assure I got the upper end of the OLD J306 90 100°C Vis chart.

How so?
A straight 90 would not have any VI improvers.
Additionally if the OEM calls for a 90 weight 110 may be too thick for the application

 

[SargeBB]

Originally Posted By: salesrep
Originally Posted By: Pablo
Searching for a straight 90 goes against most all of BITOG learning.

If I had an app that required SAE 90, I would use 75W-110 to assure I got the upper end of the OLD J306 90 100°C Vis chart.

How so?
A straight 90 would not have any VI improvers.
Additionally if the OEM calls for a 90 weight 110 may be too thick for the application
If memory serves correctly, until several years ago, cSt for SAE 90 actually included what is currently SAE 90 and SAE 110. Feeling that 90 encompassed too great a weight span, SAE 110 was established to divide 'old' 90 approximately in half, and the "new" 110 became the upper half of the old 90. I didn't explain very well, but the bottom line is this: the viscosity of 110 is not thicker than the upper range of the older 90 weight GL-5.

 

[MolaKule]

Originally Posted By: salesrep
Originally Posted By: Pablo
Searching for a straight 90 goes against most all of BITOG learning.

If I had an app that required SAE 90, I would use 75W-110 to assure I got the upper end of the OLD J306 90 100°C Vis chart.

How so?
A straight 90 would not have any VI improvers.
Additionally if the OEM calls for a 90 weight 110 may be too thick for the application


Pablo and Sarge are correct.

Look at the read-across viscosity chart on BobIsTheOldGuy front page.

The upper end of a 90 weight gear oil is about 22.5 cSt.

Now look at Amsoil and Redline 75W110 specs:

Kinematic Viscosity @ 100°C, cSt (ASTM D 445)
21.3

Vis @ 100°C, cSt 20.87

 

[Whitewolf]

GM part # 88863089 I think will do it.