Recommended gear oil?

I would not run a synthetic if you are planning on doing any towing or offroading. Currie did tests a while back after a few warranty claims on their axles and it wasn't until they tested synthetic vs conventional that they realized the conventional is better at heat transfer and the synthetic was causing their issues.

I've been changing out my fluids considerably more often than is needed due to various work. With my numerous water crossings I aim for once a year (in the fall so water won't freeze in them over the winter) which tends to be about every 8k miles. It all depends on what you're doing with them imho some people will be fine at 20k+ I'm sure.

Mr. Bills said:
FYI for anyone who reads the study - It was commissioned by and paid for by Amsoil.

If anyone thinks that it is coincidence that Amsoil scored highest of the gear oils tested should contact me immediately. I have some swamp land and a bridge that you might want to buy.
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Amsoil tends to be pretty good stuff. Anything that they have formulated to spec I run. You might want to actually look into it before bad mouthing it.
 
Sancho said:
I just changed engine oil.. as in tuesday.... is it weird that I want to change it again just to flush out as much crap as possible?
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I don't know the current condition of your engine or it's history. Rather than waste oil you should consider sending a sample into Blackstone after 1k miles if you're worried about it.
 
toximus said:
I would not run a synthetic if you are planning on doing any towing or offroading. . . .
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I use Valvoline High Performance 85W-140 conventional GL-5 gear oil in my Rubicon Dana 44 axles. However, those with clutch-based traction devices need a friction modifier that is sometimes not found in conventional gear oil. If for no other reason than peace of mind they would be better off with synthetic gear oil because it nearly always contains the necessary additives in the proper concentration. [Calculating the amount and adding additives to differentials is a hassle.]

The differences in heat dissipation qualities between synthetic and conventional gear oil that were observed by Currie may matter under the extreme conditions encountered by competitive rock crawlers and racers, but don't really matter much to the majority of the jeeping community.

With stock axles one can't go wrong by following the manufacturer's specifications. For those with aftermarket gears, lockers, etc., use what the gear installer or gear manufacturer recommends.
 
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It is very hard to find a conventional GL5 gear lube without the friction modifier additive. I use nothing but conventional gear lubes and never saw one without it.

Many high end custom axle manufacturers like Currie require customers use only conventional gear lubes or risk voiding the warranty.
 
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Jerry Bransford said:
It is very hard to find a conventional GL5 gear lube without the friction modifier additive. I use nothing but conventional gear lubes and never saw one without it.

Many high end custom axle manufacturers like Currie require customers use only conventional gear lubes or risk voiding the warranty.
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That was my experience buying oil for the Truetrac, which needs conventional per recommendation. Only one I found local was Napa brand. No qualms using theirs, likely just a re-branded Valvoline or similar.
 
Jerry Bransford said:
It is very hard to find a conventional GL5 gear lube without the friction modifier additive. I use nothing but conventional gear lubes and never saw one without it.
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There are some specialty brands without the friction modifier, also limited application products by major brands such as Castrol, but you are correct that the GL-5 gear oil one typically finds on the shelves at chain parts stores has it.

The phrase "compatible with limited slip differentials" on the label or something similar offers some reassurance to the casual home mechanic that s/he is buying the right stuff. But sometimes the labels are silent as to whether or not the contents have friction modifiers or are compatible with limited slip units. For example, the Valvoline High Performance conventional Gear Oil I prefer says nothing on the label one way or the other. One has to download and read the Product Information Sheet to find the language, " . . . has limited slip additive included for applications calling for limited slip gear oils and does not need additional limited slip friction modifiers (Ford M2C118A, Chrysler MS-5630, or GM1052358) added in most vehicles." How many consumers actually take the time to read the Product Information sheet?
'

But as I said, it is nearly impossible to go wrong with any GL-5 gear oil consistent with the manufacturer's recommendations.
 
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I mean, if we're really going to get picky here, Torco or get out. Oh and you'll have to add your own modifiers because it's a real mans oil. ;)

Seriously though, 95% of what you find on the shelf will just work. If you're doing extreme wheeling with high shock loading etc then look into the better brands.
 
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toximus said:
I mean, if we're really going to get picky here, Torco or get out. Oh and you'll have to add your own modifiers because it's a real mans oil. ;)

Seriously though, 95% of what you find on the shelf will just work. If you're doing extreme wheeling with high shock loading etc then look into the better brands.
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Torco is great gear lube, I used to run it years ago but it's just impossible for me to find locally so I run Valvoline conventional 85W-140. It's likely equally great for my uses. :)
 
Rob5589 said:
That was my experience buying oil for the Truetrac, which needs conventional per recommendation. Only one I found local was Napa brand. No qualms using theirs, likely just a re-branded Valvoline or similar.
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Chevron Elo Gear ESI 80W-90 is what I am using in my Tru Trac. It is a non synthetic GL-5 gear oil ordered from Walmart via internet.
 
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