Tell that to Currie, Revolution Gear and Axle, Dynatrac, Yukon Gear, G2, ECGS, etc. and see what reaction you get on that claim. Every single one of those recommend conventional gear lube for their axles and gears.
Can synthetic be used in a factory axle with its pre-lapped gears and for Mon-heavy duty uses? Obviously, it's OK in those. But for harder uses or for aftermarket products like mentioned above a conventional is the way to go. And as with the above product names, the factory gears will also run cooler with a conventional.
I'll never run another synthetic gear lube again in my axles after first being educated about the problem by John Currie. They require a conventional gear lube in their axles and will void the warranty if a problem occurs and they determine it was filled with a synthetic.
This info is for everyone else since I know you'll disagree. I don't really care that you'll disagree.
For everyone else this gives a little more of my history with how I became so adamant on this subject...
https://wranglertjforum.com/threads/rubicon-dana-44-gear-oil-recommendations.18853/#post-305581
You don't care right up to the point of....
Replying to my post.
See this is what I find amusing by you. You will beat the OEM drum all day long...unless...it goes against some strange thing that tickles your fancy. Then OEM don't mean shit.
Ooohh but wait...2 moments later you go right back to making OEM love.
See this is what I know..from real world actions. I don't need a fucking article or copy and paste some shit. Matter of fact I don't even need that one time at that one place with that one guy on that one obstacle at that one day of weather that we had that one thing not perform good...to give an example.
(I love those ones that you do)
Allow me to explain a little more clearly for you...
#1 we aren't talking about a Currie built axle..are we?
Matter of fact we aren't talking about any axles built by anyone.
These are factory axles that got a gear change. Big effing deal.
If I'm running a $$$5 large Currie built axle and their warranty parameters state I must run xyz...I'm running xyz. Doesn't matter to me how the nerds got their data..I'm not voiding a warranty. They could tell me they'll only warrant axles run with old French fry grease. Guess what...I'm dumping the fry daddy. It's what the mfg is recommending.
#2 Let's just focus on the OP's axle with a Detroit.
They specifically state to use the mfg recommended gear lube. Right? Don't answer that...trust me. It's what they say.
#3 Now I know this will go against your thinking at present but let's use what the OEM recommends.
So for normal driving with the above axle...they recommend a GL-5 80w-90.
Ooohhh but hold the phone...for heavier use like towing and the like (which generates more stress and heat) they recommend 75w-140 synthetic.
#4 considering what the subject is here...factory 30/35's...running factory or close to horsepower...
(These can only tow so much regardless and if the 30 and or (more likely) 35 were to implode...it will be from deficiency in strength/owner abuse with absolutely nothing to do with lube type...in the subject axles here.
#6
Running synthetic in the subject axles benefit's are far greater than not and will have absolutely positively zero negative effect.
Not one!
#7 for every article you want to hang your hat on I can show you an equal number of examples that state otherwise.
Have you really looked at just how much these trucks of today can tow and the power/torque.
What do they recommend?
Synthetic. I'll be dammed.
#8 we've changed hundreds upon hundreds of diff fluids over the years. Never an issue. Not ever once.
Good day
