M1 75W90 LS in regular differential

[DrRoughneck]

It seems all Mobil 1 75W90 lubricant is rated "LS" on the bottle and come with friction modifiers needed for limited slip differentials.

Is it safe to use in a standard non-limited-slip differential?

 

[KD0AXS]

Yes

 

[440Magnum]

Yes, you would be hard-pressed to find a truly FM-free GL5 gear oil these days... not that you'd really want one. The FM's certainly don't hurt gear lubrication and might even help in a very 3rd-order kind of way compared to the EP additives.

 

[1000MPH]

I use Delvac over M1 just to be different.
http://www.mobil.com/USA-English/Lubes/P...90_80W-140.aspx

 

[DrRoughneck]

Originally Posted By: 1000MPH
I use Delvac over M1 just to be different.
http://www.mobil.com/USA-English/Lubes/P...90_80W-140.aspx

It seems it sells by the gallon, which is more than what I need. Do you know what's its shelf life?

 

[barkingspider]

No problems, I have used Mobil 1 and valvoline 75w90 LS in many non LS applications. Good to go

 

[mjoekingz28]

Is the LS additive used to increase friction like MTFs dont like to be too 'slick' to allow for proper synchronizer engagement?


Also, what elements/minerals are usually used to spike a gear oil for it to include limited- applications?

 

[mjoekingz28]

Per GM,

"...the additive reduces friction between your limited-slip or positraction differential friction plates to eliminate the annoying chatter that is common with these types of units. ". It goes on to say it not only quiets your rear-end, but it can also aid in your differential's ability to apply and release the clutch smoothly....

 

[DrRoughneck]

Originally Posted By: mjoekingz28
Per GM,

"...the additive reduces friction between your limited-slip or positraction differential friction plates to eliminate the annoying chatter that is common with these types of units. ". It goes on to say it not only quiets your rear-end, but it can also aid in your differential's ability to apply and release the clutch smoothly....


Sounds like better lubricity with same viscosity. So better for open diff, right?

 

[zeng]

Originally Posted By: DrRoughneck
It seems all Mobil 1 75W90 lubricant is rated "LS" on the bottle and come with friction modifiers needed for limited slip differentials.
Is it safe to use in a standard non-limited-slip differential?



ZDDP/EP and other FM's acts in between gear teeth sliding.

The 'LS' acts on the interface in between the friction clutch discs and steel friction plates..... I suppose 'LS' doesn't interfere with gear teeth sliding action.

 

[440Magnum]

Originally Posted By: mjoekingz28
Is the LS additive used to increase friction like MTFs dont like to be too 'slick' to allow for proper synchronizer engagement?


No. They're more like the FMs used in ATF to prevent torque convertor clutch shudder. What they do is bring the dynamic and static coefficients of friction of the limited slip clutches closer together so that the clutch makes a smoother transition from "slipping" to "locked." Without the FM, the clutch will grab, hold, slip, repeat causing a lot of vibration and even possible wheel hop when making sharp turns.

 

[DrRoughneck]

Originally Posted By: 440Magnum

No. They're more like the FMs used in ATF to prevent torque convertor clutch shudder. What they do is bring the dynamic and static coefficients of friction of the limited slip clutches closer together so that the clutch makes a smoother transition from "slipping" to "locked." Without the FM, the clutch will grab, hold, slip, repeat causing a lot of vibration and even possible wheel hop when making sharp turns.


Great explanation, thanks.

So for an open differential, with no clutch, these do not cause any adverse effect then?

 

[Whimsey]

I have Mobil 1 LS 75W-140 in my non ls rear diff for the last 20,000 miles and it's whisper quiet and smooth.

Whimsey

 

[DrRoughneck]

Originally Posted By: Whimsey
I have Mobil 1 LS 75W-140 in my non ls rear diff for the last 20,000 miles and it's whisper quiet and smooth.

Whimsey

Which vehicle is it?

 

[zeng]

Originally Posted By: DrRoughneck
Originally Posted By: 440Magnum
No. They're more like the FMs used in ATF to prevent torque convertor clutch shudder. What they do is bring the dynamic and static coefficients of friction of the limited slip clutches closer together so that the clutch makes a smoother transition from "slipping" to "locked." Without the FM, the clutch will grab, hold, slip, repeat causing a lot of vibration and even possible wheel hop when making sharp turns.

Great explanation, thanks.
So for an open differential, with no clutch, these do not cause any adverse effect then?



You're right.