Rubicon Dana 44 Gear Oil Recommendations?
- Thread starter AndyG
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Happy in Montana
Member
Torco is a great brand but I'll never run another synthetic gear lube in my axles. Against my better judgement I got talked into using a synthetic gear lube for my last regearing and my rear gears got too hot during an easy break-in causing them to start whining. The gear guy that installed the replacement gears immediately told me the problem was heat related when he got the rear gears out and it definitely wasn't from my extra-careful break-in. It is a proven fact that the gears run hotter when lubed with a synthetic than they do a conventional. Surprising to many but it's true. That's why companies like Currie and Revolution Gear specify conventional gear lubes for their axles & gears.
For one example, this is what Revolution Gear says at https://www.revolutiongear.com/ring_and_pinion_break_procedure
"Recommended gear oil is an 85-140W, Non-Synthetic, GL5 grade or Higher, Name Brand Oil "
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gg1
TJ Enthusiast
Just to add, my mechanic uses regular gear lube not synthetic as well. I agree with Jerry. My mechanic is a close friend and works on countless Jeep etc.
Happy in Montana
Member
In total agreement. Torco RGO is not synthetic, has that nice sulfur smell we grew up with. Their SGO is however.
I don’t mean to beat a dead horse, but, I’m not sure what to use.
I have a 2004 Jeep Wrangler. I have Dana 44 front and back, with ARB air lockers, as well as 33’s. I do some off-road and I’m not hard on my vehicle. I normally use a synthetic oil. I need to change the gear oil and I don’t know which to use. Can you, please give me a suggestion. I’m not very technical and my brain implodes, when y’all get into numbers and ratios. I do live in a hot environment (5-10 degrees lower, than Las Vegas, Nv)
I have a 2004 Jeep Wrangler. I have Dana 44 front and back, with ARB air lockers, as well as 33’s. I do some off-road and I’m not hard on my vehicle. I normally use a synthetic oil. I need to change the gear oil and I don’t know which to use. Can you, please give me a suggestion. I’m not very technical and my brain implodes, when y’all get into numbers and ratios. I do live in a hot environment (5-10 degrees lower, than Las Vegas, Nv)
Just use what your manual states.
I’m sure the 2005 manual is the same as 2004.
https://wranglertjforum.com/threads/rubicon-dana-44-gear-oil-recommendations.18853/post-305616
Carve
TJ Enthusiast
It sounds like they tested this, and also have the anecdotal experience of the failures, but this makes absolutely no sense. Specific heat capacity is marginally higher in synthetics which should make them better at heat transfer, not to mention they require fewer multi-viscosity additives so have more oil there to do the actual lubrication instead of being more additive-heavy.
My mechanic friend also recomends 85W-140 non synthetic. They have that in STP brand at my local AutoZone, so that's what I'll use, but this just doesn't make sense. Has anyone figure out WHY the ring and pinion run hotter with synthetic?
It's not anecdotal experience, it was discovered during controlled lab tests at Currie Enterprises. Currie was having a huge failure rate of new properly installed R&P gear sets in new axles they were selling. It started when people started using synthetics in brand-new aftermarket axles though they didn't of that connection at the time... they only knew that their warranty rate was skyrocketing and it was an expensive issue. They were as shocked as anyone to finally figure out that the failing axles had all been filled with synthetic gear lubes. It took them a long time to sort through that and it required specially designed test jigs that could measure the temperature of the R&P gears directly. That was only after the misleading results of the differential covers being cooler when there was synthetic gear lube inside. That was determined to be that because the synthetic was not sinking (extracting) the heat out of the gears as well, the heat in the gears wasn't making it through the synthetic gear lube to the diff cover.
Here's another example saying to use a synthetic during the critical break-in process... Revolution Gear & Axle. "Recommended gear oil is an 80W-90 or 85W-140, Non-Synthetic, GL5 grade or Higher, Name Brand Oil" at https://www.revolutiongear.com/ring_and_pinion_break_procedure
After the gears are completely broken in you could, if you really wanted to, switch to a synthetic. Not me, I already lost a set of gears by having broken them in while using a synthetic gear lube. The gear guy who replaced them looked at the newly broken in gears and said they overheated and said "you use a synthetic didn't you!".
Whether or not it makes sense to you doesn't really matter... it's proven and well-known in the industry that gears run much hotter during the break-in process when lubed with a synthetic gear lube. Personally I'll never run another synthetic gear lube again in my Jeep when breaking in new aftermarket gears. I learned that lesson the hard way and it's why I stress it to anyone about to install new aftermarket gears.
Carve
TJ Enthusiast
Yeah I mentioned both of those things- the higher temperature during testing, and the anecdotes of the higher failure rate. Synthetic has a marginally higher heat capacity though so it *should* carry heat away slightly better. I found a video by Dynatrak where they say "some synthetic oils have properties that interrupt the flow inside the housing", so it must be that. That's so weird though because shouldn't the "flow" be determined by the viscosity? I wonder how they determined this? I mean...it's gear oil...it needs to stick to the gears and "flow" to lubricate everything. It's about a minute in in this video...
It'd be nice to know which synthetics have this "flow" shortcoming, and why...if that's the actual problem. Synthetic does lubricate better, lasts longer and has a slightly higher heat capacity so it's preferable...so long as it gets to where it needs to be. In the mean time, I got some STP 85W-140 at my local AutoZone for my front diff. Should I just use that in my rear diff, too, or do you recommend this Lucas conventional GL-5 gear lube. I'm in a Rubi with an LSD.
It'd be nice to know which synthetics have this "flow" shortcoming, and why...if that's the actual problem. Synthetic does lubricate better, lasts longer and has a slightly higher heat capacity so it's preferable...so long as it gets to where it needs to be. In the mean time, I got some STP 85W-140 at my local AutoZone for my front diff. Should I just use that in my rear diff, too, or do you recommend this Lucas conventional GL-5 gear lube. I'm in a Rubi with an LSD.
Enough of this oil shit.
This is what has been noticed, assumption was made, and test very likely proved the theory.
Take it or leave it.
There is decades worth of oil this and oil that on the internet to read, and to this day no end to it in sight. One has to be a complete fucking moron to continue this never ending circles of retardation.
This is what has been noticed, assumption was made, and test very likely proved the theory.
Take it or leave it.
There is decades worth of oil this and oil that on the internet to read, and to this day no end to it in sight. One has to be a complete fucking moron to continue this never ending circles of retardation.
You're overthinking this.... just run a good brand of conventional GL-5 gear lube like Valvoline, Mobil, Torco, NAPA, Castrol, etc. and be done with it. Lucas is ok too but it's just priced higher for no additional benefits. Don't get into analysis paralysis over gear lube, any major brand of conventional GL-5 gear lube will work just fine.
If you absolutely won't be able to sleep at night without a synthetic gear lube in your axles, go ahead and install it the next gear lube change interval AFTER the gears are fully broken in. The gears will still run hotter but if you insist, it's your Jeep.
Carve
TJ Enthusiast
No need to get hostile- if you read my posts I'm obviously "taking it" and just got some conventional gear oil. I'm just trying to understand it because it doesn't make sense. Why would you NOT want to understand it?
Or run a set of OEM gears from genuine USA made Dana/Spicer. On the flip side, their ring and pinion gear ratios are not at plentiful as the aftermarket offerings when it concerns the TJ/LJ Dana 30, 35, and 44.
As Jerry mentioned, the aftermarket gears arent built to the highest quality that would match the Dana/Spicer OEM gear sets. I believe the Revolution stuff is made in China, Korea, or somehwere over in Asia. Same with Yukon, who imports from India.
As Jerry mentioned, the aftermarket gears arent built to the highest quality that would match the Dana/Spicer OEM gear sets. I believe the Revolution stuff is made in China, Korea, or somehwere over in Asia. Same with Yukon, who imports from India.