Opinion - Synthetic Gear Oils in General

[UNC151]

Thanks to Pablo I signed up as an Amsoil preferred customer and receive their magazine as it is distributed. Because I have been performing quite a bit of axle maintenance lately an article entitled A Closer Look At Gear Lube caught my attention (though this web article is edited and does not contain the full magazine text). IMHO, Amsoil gear oil is arguably the best on the market today and understandably the article is touting synthetic gear oil in which they use scenarios like the one below as reasons why synthetic is a better choice. Without this becoming an Amsoil bashing thread, what are your thoughts about synthetic gear lubes in general--good, bad, or indifferent?

Excerpt from the magazine article:

Automakers continue building vehicles that produce substantially more horsepower, torque and towing capacity than their predecessors, yet differential gears and bearings responsible for converting this increased power into wheel rotation remain largely unchanged. To reduce drag and improve fuel economy in some vehicles, engineers have also reduced the volume of gear lube available to cool and protect. The 1996 Ford F-250 Crew Cab, for example, features a 10,500-lb. maximum towing capacity using a differential that holds 3.75 quarts of gear oil. The 2016 Ford F-250 Crew Cab, meanwhile, boasts 12,500 lbs. of maximum towing capacity despite a rear differential with a smaller 3.5-quart capacity. Increased towing capacities plus reduced lubricant volume create severe conditions best suited for synthetic lubes such as extreme heat, added pressures, and increased likelihood of wear.

 

[SOHCman]

I could have sworn I read that on their site before...

I cant think of anything but benefit from a syn, and Amsoil is some of the best. why risk it?

 

[Inspecktor]

I use Severe Gear in my vehicles, including the GL1200. I think it is some of the best stuff out there.

 

[sciphi]

Either better protection or longer service life. Why not? Cheaper in the long run for most folks. Maybe not in money, but opportunity cost.

 

[Rand]

If there was one AMSOIL product I was going to buy..

It would definitely be their gear oil.

 

[umungus1122]

Since it's serviced infrequently, why not use a syn? You can get Mobil 1 75w-90 at AAP for about $8-9 a qt. with codes.

 

[HerrStig]

Originally Posted By: 2015_PSD
Thanks to Pablo I signed up as an Amsoil preferred customer and receive their magazine as it is distributed. Because I have been performing quite a bit of axle maintenance lately an article entitled A Closer Look At Gear Lube caught my attention (though this web article is edited and does not contain the full magazine text). IMHO, Amsoil gear oil is arguably the best on the market today and understandably the article is touting synthetic gear oil in which they use scenarios like the one below as reasons why synthetic is a better choice. Without this becoming an Amsoil bashing thread, what are your thoughts about synthetic gear lubes in general--good, bad, or indifferent?

Excerpt from the magazine article:

Automakers continue building vehicles that produce substantially more horsepower, torque and towing capacity than their predecessors, yet differential gears and bearings responsible for converting this increased power into wheel rotation remain largely unchanged. To reduce drag and improve fuel economy in some vehicles, engineers have also reduced the volume of gear lube available to cool and protect. The 1996 Ford F-250 Crew Cab, for example, features a 10,500-lb. maximum towing capacity using a differential that holds 3.75 quarts of gear oil. The 2016 Ford F-250 Crew Cab, meanwhile, boasts 12,500 lbs. of maximum towing capacity despite a rear differential with a smaller 3.5-quart capacity. Increased towing capacities plus reduced lubricant volume create severe conditions best suited for synthetic lubes such as extreme heat, added pressures, and increased likelihood of wear.
Another commercial.

 

[UNC151]

Deleted

 

[Garak]

How is this a commercial? It's a good basis for discussion. Is he selling Amsoil?

While I've used and continued to use a lot of conventional fluids over the years, something that almost never gets attention are things like drivetrain fluids, and whatever makes them more durable and needing less maintenance is a good thing.

By the way, ads are allowed here; the site is paid for by them. Right now I'm going to plug Pennzoil and Mobil 1. Since both are sponsors, I get to do that:

http://www.pennzoil.com/

http://www.mobil1.com/mobil1/Default.aspx

Oh, and Pablo is a paid sponsor, too, so all your Amsoil needs, please PM Pablo.

 

[oldhp]

2003 Dakota 3.9/auto, drained out the factory gear oil and used Royal Purple 75W90 syn gear oil and gained 1 MPG. Seems like the smaller the engine/weight you get better results using synthetic gear oil. Now on my 2014 RAM 1500 zero difference using Red Line 75W110 from the factory 75W140 syn oil. Before anybody starts by saying I down graded the rear gear life.....truck spends 99% of it's life going 55 MPH, I don't pull, tow or haul anything except fall leaves, so I ain't hurting anything.....and maybe I am getting .00465 better MPG.

 

[FastLane]

I swear by synthetic gear oil. Most doffs have no real cooling ability. The gears get pretty warm if you work them hard. It's a no brainer to use synthetic gear oil in diffs.

 

[rideahorse]

This is just an opinion and a commercial.
At what temp does syn become better than conventional.
At what ft pounds of torque does it become better.
How many times has your vehicle crossed over these lines and for how long.
How many dead vehicles are sitting on the side of the road with the guy saying Well [censored] I should have used syn oil.
Out of hundreds of millions of vehicles that are produced go to the junk yard and have never ever had their gear oil changed.
Look at all the Ag equipment that runs under full load in all kinds of weather for thousands of hours with conventional oil in them and have never had their oil changed.
Is syn better Um maybe By 1% by 20% they don't give you that fact.
As far as I see it it is just marketing hype.

 

[MaximaGuy]

Diff and x-case are often neglected items and many a times forget to maintain them. Putting synthetics in them gives one the peace of mind and better protection for an often neglected hardware.

 

[Ducman]

I have seen mineral oil come out of rear axles totally cooked and running out like water with a stink that can only be described as something that comes from hells kitchen.

Also I have seen a crown wheel and pinion in one particular rear axle with mineral oil that were virtually welded together. The oil was coked onto the parts it got that hot.
In that case I suspect that even a synthetic oil wouldn't have lasted very long due to the shear abuse. In all fairness from memory I think the oil was originally spec'd to be a straight 90 grade with an LSD additive?
Perhaps a straight 140 grade would've held up a bit better?

Currently, both of my best vehicles have Synthetic oil spec'd exclusively for their rear ends.
They are both what could only be described as true GT cars to give an insight into the application.

One of the vehicles has Synthetic oil spec'd exclusively for the transmission, with the other only having a group III oil carrying an approval by the manufacturer.

Both the engines in the vehicles have a variation of full synthetic oil spec'd exclusively.


To my way of thinking that's a conclusive endorsement for the synthetic technology.

 

[UNC151]

Originally Posted By: rideahorse
This is just an opinion and a commercial.
At what temp does syn become better than conventional.
At what ft pounds of torque does it become better.
How many times has your vehicle crossed over these lines and for how long.
How many dead vehicles are sitting on the side of the road with the guy saying Well [censored] I should have used syn oil.
Out of hundreds of millions of vehicles that are produced go to the junk yard and have never ever had their gear oil changed.
Look at all the Ag equipment that runs under full load in all kinds of weather for thousands of hours with conventional oil in them and have never had their oil changed.
Is syn better Um maybe By 1% by 20% they don't give you that fact.
As far as I see it it is just marketing hype.
I would disagree that it is simply marketing hype. Whether or not a person needs synthetic gear oil is a different matter. At what temperature is a synthetic better than conventional? Simple--the extremes. There is a video on Youtube comparing conventional gear oil to synthetics and at each end of the scale synthetics outperformed the conventional by leaps and bounds (not only by 1%--and how is that measured anyway?). If synthetics were just a marketing tool, then why do most (if not all) of the OEM truck manufacturers use it in the rear axles?

 

[Garak]

Exactly. If I were to change differential fluid on a reasonable schedule, and conventional were permitted in the application, great. But, when it comes to differential fluid, there are a few issues. First, it isn't always easy to change. People who aren't mechanics often prefer not to mess around with gaskets, and not all have drain plugs. Secondly, in either case, the fluid often gets neglected and never touched. Sure, it may never "have to" be changed, at least from a service interval standpoint. A synthetic would have advantages for the lubricant longevity.

Cost is also an issue. Unlike conventional versus synthetic motor oil, at least here, the price difference in marginal. While PP at regular price is double the price of regularly priced Pennzoil conventional, RP gear oil is like 10% more than Pennzoil conventional gear oil.

Of course, for fleet usage, things might be different, and one would have to call a distributor to compare costs by the pail of different products, and see what kind of service intervals they could get.

 

[UNC151]

Originally Posted By: Garak
Cost is also an issue. Unlike conventional versus synthetic motor oil, at least here, the price difference in marginal. While PP at regular price is double the price of regularly priced Pennzoil conventional, RP gear oil is like 10% more than Pennzoil conventional gear oil.
Indeed. It can also depend on the viscosity of the gear oil too--do they even make a non-synthetic 75W-140 (as an example)? I do not think so, you would have to switch to 85W-140. Amsoil 75W-140 is $11.85 a quart versus $7.00 or so for something like Valvoline 85W-140. For a $5.00 difference per quart the choice is clear for me.

 

[tig1]

I used M1 75-90 in my old Ford Ranger with 354K and only changed the lube twice. I'm sure your Ford has syn as the FF.

 

[Garak]

Yes, viscosity specifications often dictate what one buys, too. Here, we're often looking at $22 to $25 for a quart of Pennzoil gear oil (regular price) versus $26 to $28 for a quart of a synthetic, including the boutiques. As I mentioned, for the pails, I'm not even sure these days as to the pricing or the difference in pricing.

 

[Y_K]

Mr Doug Hillary posted a few times here on the actual benefits of the syn gear oil in his OTR fleet in many million miles of studies in AU. Lower temps and healthier longer living seals off the back of my head.
That being said, I used Delo ESI extensively along with various syn gear lubes.

That old Amsoil comparison 'test' was cooked to make it look the best, of course. But it is not important really. Buy what you want.