85-140 question

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Hi,
Did several searches of forums on this question but found nothing related, so I hope I'm asking this on the right forum:

Finishing up a rebuild of a steering box from a 1960 Ford tractor. Shop manual spec calls for 90W gear oil. These old boxes are famous for leaking/seeping even after a rebuild, new seals, etc. I've seen a recommendation to use 140W instead, but that's not available in less than 5 gal quantities - I need 1 qt.

I can buy 85-140 in quarts. Is 85-140 really 140W that acts like 85W when cold, or is it really 85W that acts like 140W when hot?

In our warm climate, cold-weather operation is not an issue.
 
Synthetic leans toward a 140 that acts like 85 when cold. Dino leans toward an 85 acting like a 140 when hot. It's not something that's cut and dry though. I use syn if it doesn't leak much and if it sees a lot of heat. Dino for the leaky slow pokes in the shop.
 
Originally Posted By: Ramblejam
This is the appropriate product for your application: http://www.messicks.com/part/9821006/case-1-qt-gear-grease

They're proud of it ($$), but you only need a quart, and it does a good job in these old boxes.




I'll look into that, possibly one of the CNH dealers around here has it. Quick research on the interweb tells me it is a "pourable" grease - heavier than 90W but not like bearing grease.

Thanks much!
 
Originally Posted By: RedOakRanch
Synthetic leans toward a 140 that acts like 85 when cold. Dino leans toward an 85 acting like a 140 when hot. It's not something that's cut and dry though. I use syn if it doesn't leak much and if it sees a lot of heat. Dino for the leaky slow pokes in the shop.


Thanks, I thought I'd read something about dino vs. synthetic in multi-vis lubricants. Wasn't sure if that applied to a gear oil.

Good info.
 
With something like a steering box that likes to leak, in warm climate, I think I would use a "OO" grease. Any Snapper dealer should have it.
 
Originally Posted By: old1
With something like a steering box that likes to leak, in warm climate, I think I would use a "OO" grease. Any Snapper dealer should have it.


Another good suggestion - thanks!
 
Originally Posted By: RedOakRanch
Synthetic leans toward a 140 that acts like 85 when cold. Dino leans toward an 85 acting like a 140 when hot. It's not something that's cut and dry though. I use syn if it doesn't leak much and if it sees a lot of heat. Dino for the leaky slow pokes in the shop.


Aren't most,and possibly all,dino 85W140 and synthetic 80W140 gear oils without VII's ?
blush.gif
 
Originally Posted By: zeng


Aren't most,and possibly all,dino 85W140 and synthetic 80W140 gear oils without VII's ?
blush.gif



Gear Lubes contain VII in order to meet a specific viscosity target.
 
Molakule,
I think that Zeng is getting at most of the 85W140 dinos that I've come across have a VI of 100, i.e. they seem to be base oil, no VII.

Thus the statement.

So is it true that the grade can be achieved with base oil only and PPD, rather than bolstering a base with VII ?

The 80W140s and 75W140s definitely appear to contain VIIs.
 
Originally Posted By: Shannow
Molakule,
I think that Zeng is getting at most of the 85W140 dinos that I've come across have a VI of 100, i.e. they seem to be base oil, no VII.
Thus the statement.
So is it true that the grade can be achieved with base oil only and PPD, rather than bolstering a base with VII ?

Spot on.
That's exactly what goes thru my mind.

Originally Posted By: Shannow
The 80W140s and 75W140s definitely appear to contain VIIs.

Thanks.
Would appreciate to learn what's your thoughts on my rule of thumb VI# as demarcation line (yes,it's not scientic,thus no proofs) guesstimating oils with zero or minimal VII's as follows:
a )VI# up to 100-103 (For minerals free of VII's);
b )VI# up to 120-125 (For synthetic blends free of VII's); and
c )VI# up to 140-145 (For Grp III+ full synthetics free of VII's).
Yes, I'm fully aware add packs are proprietary and non-transparent.
smile.gif
 
Originally Posted By: Shannow
Molakule,
I think that Zeng is getting at most of the 85W140 dinos that I've come across have a VI of 100, i.e. they seem to be base oil, no VII.

Thus the statement.

So is it true that the grade can be achieved with base oil only and PPD, rather than bolstering a base with VII ?

The 80W140s and 75W140s definitely appear to contain VIIs.


Most mineral oil GL's will contain both VII's and PPD's.

Full Synthetic base oil GL's contain a small amount of VII, if needed, to get to requested target specs.

What we attempt to do for full synthetic GL's is to select those base oils of various viscosities with the best Low temp and high temp specs (largest VI's) and then add only enough VI to fill out the VI spec of the finished product.

It is customary in the art to select Low Vis base oils with the best low temp characteristic and then add a lower percentage of High Vis, High VI base oils for high temp, thick film protection.

And then add just enough VII to widen the VI spec a bit according to customer requirements.
 
Last edited:
Originally Posted By: zeng



Would appreciate to learn what's your thoughts on my rule of thumb VI# as demarcation line (yes,it's not scientic,thus no proofs) guesstimating oils with zero or minimal VII's as follows:
a )VI# up to 100-103 (For minerals free of VII's);
b )VI# up to 120-125 (For synthetic blends free of VII's); and
c )VI# up to 140-145 (For Grp III+ full synthetics free of VII's).
Yes, I'm fully aware add packs are proprietary and non-transparent.
smile.gif



There are so many approaches to GL formulation that none of the above would be valid rule of thumbs.

For a quick overview of GL formulations see:

Gear Tribology and Gear Lube Formulations
 
BTW, the original White Paper referenced is still valid in terms of ratios.

The only thing that has changed recently is the improved additive packages.

The improved additive packages generally contain less buffered sulfur and increased levels of phosphate esters, better oxidants, and better corrosion inhibitors.
 
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Amsoil makes a 180 or thereabouts, and even a 250. I'm using the 180 in the Angle drive gear box on my Slingshot and its pourable. Manual calls for 80-140 but gears are noisy so I'm trying the heavier straight weight to help quieten it down.
 
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