Nissan Frontier; question about differential lube choices

[Apples]

I love my Truetrac in my 93 C1500. It is fabulous in the snow and on ice as I have not gotten stuck since I had it installed 4 yrs ago. And yes 80w90 is all you want to put in there. I am saving up to hopefully have one installed in my new 94 F350, open diff

Thank you for the feedback!

I do not mean to threadjack but I will respond to your point: I actually called EATON and spoke to the man who picked up the Detroit Truetrac tech line... to ask him directly about their Owners Manual-published rec of 80W-90, that I had been looking specifically for a lube with no added friction modifiers, etc... and that my installer for the new ring-and-pinion used an 85W-140...

To which he replied in so many words, "the difference in the -90 and the -140 as to the torque bias ratio being dependent on designed internal friction of the unit, you more than likely will not be able to notice. Carry on." And as to the amount of lubes on the shelf today that have added friction modifiers he said the same thing: That I would not be able to notice. He said of course we do not wish to add any on top of that. I mentioned I would be using a lube distinctly devoid of any FMs as per EATON's published recs but with the slight variation on lube viscosity.

As to the use of synthetic axle lube for the Truetrac, he mentioned that there had not been enough testing done by EATON for them to recommend it's use, first of all, and secondly, the change in internal friction may be so much that the unit's torque bias *may* be altered to the point of diminished performance (although with no harm to the unit itself).

 

[DadTim@No1]

I don't have an answer for you but I do have a use case to report.

I have just had installed an EATON Detroit Truetrac helical gear-type limited slip differential in the rear axle of my 2016 Ford F150... and in EATON's manual supplied with the diff it states: 80W-90 conventional lubricant.

Apparently, since the lubricity of synthetic oil seems to be so much more "slick" it can change the torque bias imparted by the design of this helical-gear differential. Same reason they suggest "no friction modifier/s" - it can change friction levels, or the amount of friction at the interface of the differential body and the helical pinions and how they transfer torque from one side gear to the other.

And stuff like that. I don't know. I'm just a cave man. But there's one thing I do know! and that is that I'd like to stick with using a conventional oil in this application. I will use a synthetic oil or a synthetic blend for other machinery than my truck's drive axle differential.

Now to us non professionals, that sounds like a more valid reason to use the 80/90... However, Nissan Rouges for example, don't have the design of the Eaton ( please correct me if I'm wrong ) soooo.... if one were to switch it seems like you should change the front and rear at the same time with the same oil to avoid what was described to you as far as lubricity A few months ago I changed the front and rear diif's in my 2019 Nissan Rogue with the 80/90 but I would have liked to go with the 75/90 for obvious reasons.. I had called three Nissan dealerships and was very dissappointed in the answers they gave... in other words no one knew for sure. Answers ranged from " Nissan reccommends " to " I use 75/90 in mine ".. This shouldn't be rocket science..

 

[Shel_B]

@Rally2045 I would use a synthetic 75W110 because it has better both low and high temperature performance and thicker oil film.

I imagine VIs are used in these lubricants. Are they subject to shear and breakdown like those in motor oil? Are there different grades/qualities of VIs for gear oil as there are for motor oil?

 

[Shel_B]

and that is that I'd like to stick with using a conventional oil in this application. I will use a synthetic oil or a synthetic blend for other machinery than my truck's drive axle differential.

Why is that?

 

[MolaKule]

I imagine VIs are used in these lubricants. Are they subject to shear and breakdown like those in motor oil? Are there different grades/qualities of VIs for gear oil as there are for motor oil?

VII's are used with specific VII's used in the formulations.

 

[MolaKule]

As to the use of synthetic axle lube for the Truetrac, he mentioned that there had not been enough testing done by EATON for them to recommend it's use, first of all, and secondly, the change in internal friction may be so much that the unit's torque bias *may* be altered to the point of diminished performance (although with no harm to the unit itself).

And therein lies the contradiction. "May" and "possibly" seem to be their key words. Why does Nissan specify Synthetic lubes in their Torsen type differentials?

This "possibly" of "altered" bias has never been proven or measured.

 

[MolaKule]

I guess I am confused as to why it specifically says "Genuine NISSAN Differential Oil Hypoid Super GL-5 80W-90 ( con-ventional oil) or equivalent" Is this just some kind of cost savings for service plans like some people have suggested on the owner forums?

No it will not damage anything. Conventional gear lube is cheaper than synthetic lubes and the front differential does not work as much or as hard as the rear differential. A good synthetic 75W90 will suffice.

 

[D1dad]

I’ve used oem which is pennzoil, amsoil and now motul mineral. All 80w90 in our 18 rogue in the last 90k and nothing eventful to report, so I don’t know it matters and I’m in Ohio. I’ve got a bottle of Schaeffers waiting to go in next spring. If your Frontier holds the small amount that mine holds, then fresh is key. I waited till 40k to dump the factory fill and it was beyond shot.

 

[MolaKule]

I’ve used oem which is pennzoil, amsoil and now motul mineral. All 80w90 in our 18 rogue in the last 90k and nothing eventful to report, so I don’t know it matters and I’m in Ohio. I’ve got a bottle of Schaeffers waiting to go in next spring. If your Frontier holds the small amount that mine holds, then fresh is key. I waited till 40k to dump the factory fill and it was beyond shot.

@Rally2045

If your differentials are the small 8-bolt types as in my Frontier, then yearly changes are needed.


"No one is useless in this world who lightens the burdens of another."

Charles Dickens

 

[D1dad]

@Rally2045

If your differentials are the small 8-bolt types as in my Frontier, then yearly changes are needed.


"No one is useless in this world who lightens the burdens of another."

Charles Dickens

Probably different set ups. But the diff and transfer hold right around a qt together. This was a lease that I bought during Covid, so outside of oil and filters, I followed the FSM. At 40k when I bought the car I changed the drive fluids. Huge mistake. The diff fluid was actually very clean, but the transfer was bad enough to make you dry heave.