Dino or Synthetic for Differentials?

[Ducked]

Originally Posted By: 2015_PSD
Originally Posted By: LoneRanger
Originally Posted By: 2015_PSD
Originally Posted By: LoneRanger
Dino (conventional) adheres to the gears better than synthetic.
Based upon what? Any factual information to share to substantiate this statement?
Yes. Group I and II oil has better polarity. Group III, which majority of "synthetics" are today, has poor polarity for metal cling as compared to Grp I and II. Known fact and common knowledge on here.
How does that equate to less wear or longer oil life?


You mean, which is likely to wear faster, rusty initially unlubricated gears or shiny oily gears?

Ooo...let me think. Can I get back to you on that in say, 0.001 seconds?

Probably mosly significant where there is a lot of downtime, as for the farm equipment above, or my car.

I've also seen it said of engine oils in light aircraft, which spend a lot of time parked.

Longer oil life is likely to be a secondary effect. If the gears suffer more wear, the oil will have more metal in it so its likely to become less effective even though its chemical and physical properties are probably largely unchanged (though there can also be some slight catalysis of oil oxidation in the presence of metals.)

 

[CarbonSteel]

Originally Posted By: Ducked
Originally Posted By: 2015_PSD
How does that equate to less wear or longer oil life?
You mean, which is likely to wear faster, rusty initially unlubricated gears or shiny oily gears? Ooo...let me think. Can I get back to you on that in say, 0.001 seconds? Probably mosly significant where there is a lot of downtime, as for the farm equipment above, or my car. I've also seen it said of engine oils in light aircraft, which spend a lot of time parked. Longer oil life is likely to be a secondary effect. If the gears suffer more wear, the oil will have more metal in it so its likely to become less effective even though its chemical and physical properties are probably largely unchanged (though there can also be some slight catalysis of oil oxidation in the presence of metals.)
No, that is not what I mean and your sarcasm notwithstanding, what you say may be true for equipment that is little used, but I do not think it would necessarily apply to equipment that is used daily. As with any application and the choice of lubricants, it depends on many factors being considered before the the lubricant choice is made. To say that conventional gear oil is the best as the primary choice for all differentials is no different than making a blanket statement that synthetic gear oil is best as the primary choice. Again, it all depends.

 

[Whimsey]

Interestingly enough for the latest Explorer models Ford recommends 80W-90 conventional gear oil for their "rear axle" whether you're set up for towing or not. The PTU, Power Transfer Unit, calls for synthetic 75W-140. The 4WD models they don't have the usual front and rear diff's and transfer csse as the older 4WD such as our our 2005 4WD Explorer has. In the 2005 Explorer Ford recommended conventional 80W-90 gear oil for the front diff, 75W-140 for the rear diff and ATF for the transfer case, whether you tow or not. This also applied to my 2002 F-150.

Whimsey

 

[TheKracken]

I run synthetic in all my diff's. Makes me feel good inside

Sienna runs M1 and truck is running RLI and amsoil

 

[JeffKeryk]

Perhaps it depends on the vehicle. I have a lot of experience on C2 and early C3 Corvettes.
Dino is generally recommended, with the GM additive for positraction units.
I have an Auburn 3:36 in my 1968 L36; dino was recommended.
Others have successfully used Synthetics.

Having said this, I would use what the manufacturer recommends.
Heck, it ain't hardly ever changed...

 

[BlakeB]

My 07 Tacoma will not tolerate synthetic in the rear diff due to the limited slip clutches, they chatter with anything synthetic, regardless of how much friction modifier you add. I'm just using a cheap 80w90 and a bottle of champion friction modifier in it. Syn 75w90 in the transfer case and front diff. ECGS recommends Lucas 85-140 non synthetic in their units that they build and warranty.
https://www.tacomaworld.com/threads/friction-modifier-question.515054/#post-16255349
Originally Posted By: "07 sport 4x4, post: 16255349, member: 48165"
I also have an 07 with the LSD rear, currently at 82,500 miles. I've changed the gear oil in the rear diff several times, I have had good results with any 80w-90 gl4 or gl5 gear oil and a bottle of Champion LSD additive. I got the champion additive at my local O'reilly store, its pretty high on Amazon for whatever reason, I think I paid like $8. One time I used synthetic Lucas 75w90 which states on the bottle that it is for LSD rear ends...my rear diff chattered terrible with it, I drained it and went back to a cheap non synthetic 80w90 and a bottle of the aforementioned LSD additive, no issues with any non synthetic brand of gear oil i've used in the rear differential. For whatever its worth ECGS suggests that you should use non synthetic Lucas 85w140, or 80w90 for extreme cold, also see here.
I have just been using whatever synthetic 75w90 oil is available for the front diff and transfer case. Any LSD additive should work for the rear end. I have one more bottle of the champion additive and a tube of this sitting on the shelf for later, I haven't tried the Trans-x yet, but I think it should be fine. Ford also has a LSD additive that I wouldn't hesitate to run.

Keep in mind that ECGS is well known on this forum and others, they build, sell and warranty units for these trucks and many other applications every day... Lucas non synthetic is what they want you to run for their warranty purposes. With that said, any fresh, proper grade of gear oil is better than nasty worn out oil with loads of wear metals in it, in my opinion.
Lucas 85w140 gallon
Lucas 85w140 quart
Lucas 80w90 gallon
Lucas 80w90 quart

 

[Ducked]

Originally Posted By: 2015_PSD
Originally Posted By: Ducked
Originally Posted By: 2015_PSD
How does that equate to less wear or longer oil life?
You mean, which is likely to wear faster, rusty initially unlubricated gears or shiny oily gears? Ooo...let me think. Can I get back to you on that in say, 0.001 seconds? Probably mosly significant where there is a lot of downtime, as for the farm equipment above, or my car. I've also seen it said of engine oils in light aircraft, which spend a lot of time parked. Longer oil life is likely to be a secondary effect. If the gears suffer more wear, the oil will have more metal in it so its likely to become less effective even though its chemical and physical properties are probably largely unchanged (though there can also be some slight catalysis of oil oxidation in the presence of metals.)
No, that is not what I mean and your sarcasm notwithstanding, what you say may be true for equipment that is little used, but I do not think it would necessarily apply to equipment that is used daily. As with any application and the choice of lubricants, it depends on many factors being considered before the the lubricant choice is made. To say that conventional gear oil is the best as the primary choice for all differentials is no different than making a blanket statement that synthetic gear oil is best as the primary choice. Again, it all depends.


I think I said most of that, but, in fairness to manufacturers "it all depends" isn't going to look good in the owners manual.

They have to make a general recommendation that covers all likely usage patterns, including long idle times. So IF oil polarity/cling is a significant factor, as the above interesting farm equipment observation suggests, that might justify a general conventional mineral oil recommendation.

 

[clinebarger]

Originally Posted By: rideahorse
In farm equipment with gear boxes that we see that sit for 6 to 9 months at a time that have syn gear oil in them. You can see the gears will have rust on them from the oil line and up. Never have seen that with dino oil in them. The syn oil drains off of them completely with that much sit time and they have no protection.


This is a fact....

Front differentials that "disconnect" rarely call for synthetic gear oil because the ring gear & pinion stay idle when the vehicle is in 2wd......Which could be for months or years at a time.

I also break-in new gears with conventional then switch to synthetic because the gear contact areas burnish 10 times faster.

On a daily driver, If your gears have a nice burnish/polish & your LSD is compatible......NO reason not to run synthetic in a rear differential

 

[Whitewolf]

If I were you I would Get a DEXRON gear oil since they are controlled and regulated they are 75W/90 and are part synthetic, i.e. part PAO.

 

[CarbonSteel]

Originally Posted By: clinebarger
I also break-in new gears with conventional then switch to synthetic because the gear contact areas burnish 10 times faster. On a daily driver, If your gears have a nice burnish/polish & your LSD is compatible......NO reason not to run synthetic in a rear differential
As an aside, there are plenty of cars and trucks that come from the factory with synthetic gear oil in them. It does not seem to affect break-in (at least in the UOAs that I have seen).

 

[dustyroads]

Originally Posted By: Crispysea
I used dino on my diff because it cost half as much. It works fine. I don’t see much of a need for synthetic unless you pull heavy loads constantly.


I thought about using 85w140 in my pickup's rear diff because it's 25-30% the cost of M1 or Amsoil 75w140 synthetic, but I stayed with synthetic for less drag when cold. Lots of cold weather driving should more than pay for the extra cost up front.

I bought some M1 75w140 just because I don't see any reports on here from people using it. All I see are those boring (excellent) UOAs from those using Amsoil.

The front diff isn't used as much, but I think I'll still use a synthetic in there and make sure that I "exercise" the 4X4 now and then during the summer. In the winter, the front diff is used plenty.

In my OTR trucks (for the last two decades), the rear diffs have a 750k mile warranty. The only requirement is to change the factory fill at about 500k miles and use an approved lube, of course. The approved lubes are mostly synthetic but I believe that Delo (and maybe others?) have a conventional lube approved for the warranty, but I'm no longer up to date on that stuff.

 

[BrianF]

I prefer synthetic for the cold weather properties. My diff's don't sit in a heated garage, they don't receive any heat until they are driven. I don't change out oils to suit the season either.

My Trailblazer has Amsoil 75w90, my old 2011 Ram 1500 had Co-op SL 80w140 PAO based oil in its rear diff and the same will be in my 3500 come spring.

As well the Co-op SL oil comes in at around 9$ a liter all in. A far cry from what Amsoil, RP, Mobil are asking per quart.

 

[Garak]

Heck, even at regular prices here, synthetic differential fluid isn't ridiculously more than conventional. It's not the close to double the price normal spread of conventional motor oil versus synthetic.

 

[BrianF]

Back in 2012 when I put Amsoil in the Tb, I found it in Regina (Peavey Mart) for 17$ a quart all in. Conventional was sitting in around that same price. Rp, mobil and the others were north of 20$ a quart. Garak, perhaps the Canadian variants of this oil are derived from unicorns?

 

[Garak]

Oh, probably. I think I spent around $20 for the RP in my differential, and the conventionals were something like $15, so I went with the RP. Peavey Mart is a pretty good place for Amsoil.

 

[nthach]

I've always ran synthetic for axles, while it might be a simple job it's messy. Especially on a Lexus where the exhaust pipes run close to the diff and no matter how hard you try, you will get gear oil on the right/starboard pipe.

The most recent diff job I've did I filled up with ST 80-90 front and back on a friend's bucket. So far, so good.

 

[BrianF]

I believe that some OTR trucks can get extended warranty on the diffs with certain synthetic gear oils.

 

[dubber09]

My choice was Schaeffer, paid US$13.60 a quart. Great oil.

 

[MolaKule]

Originally Posted By: LoneRanger

Yes. Group I and II oil has better polarity. Group III, which majority of "synthetics" are today, has poor polarity for metal cling as compared to Grp I and II. Known fact and common knowledge on here.


There is no such thing as the "Golden Rule." It was made up by someone wanting their 15 minutes of fame.

Synthetic gear lubes (GL-5 differential lubes) have chemistry that have tackiness for cling, Group V components for polarity, Extreme Pressure components to reduce wear, anti-rust and metal inhibitors, to keep corrosion and rust at bay, and anti-oxidants to extend the life of the oil under high temps.

The advantage that Synthetic gear lubes have over conventional gear lubes is their extreme temperature operation capabilities.

 

[Sam_Julier]

Originally Posted By: MolaKule
Originally Posted By: LoneRanger

Yes. Group I and II oil has better polarity. Group III, which majority of "synthetics" are today, has poor polarity for metal cling as compared to Grp I and II. Known fact and common knowledge on here.


There is no such thing as the "Golden Rule." It was made up by someone wanting their 15 minutes of fame.

Synthetic gear lubes (GL-5 differential lubes) have chemistry that have tackiness for cling, Group V components for polarity, Extreme Pressure components to reduce wear, anti-rust and metal inhibitors, to keep corrosion and rust at bay, and anti-oxidants to extend the life of the oil under high temps.

The advantage that Synthetic gear lubes have over conventional gear lubes is their extreme temperature operation capabilities.




Mola, I have both conventional and synthetic GL-5 lubes in my stash. All meet the SAE J2360 spec per the link posted by cnewton3. All cost me $2/qt from an AZ close out. I've been using conventional in the 240 rear diffs (Dana 1031) and the Highlander diff. Only the Highlander TC gets the synthetic as it sits 2.5" from the downpipe. Any concerns here?

Sam