Dana 30 gear oil

Eddie Greenlee

Eddie Greenlee

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Hey folks, im changing my front dif. Oil in my 97 jeep wrangler tj dana 30. The book calls for 80w-90 GL-5 OR 75w-140 synthetic GL-5.
So have things changed ? or are they still the same?
 
Still the same. So long as the gear lube has the GL5 rating, the exact viscosity is not critical. Go with a heavier viscosity like 80W-120, 75W-140, etc. if you tow, or something like a 75W-90, 80W-90 etc. if you don't tow much.
 
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I believe conventional gear lube to be better if the axle is used hard. It's proven that the ring and pinion gears run cooler when lubricated with a conventional gear lube. High end HD axle manufacturers like Currie require the use of a conventional gear lube or they'll void the warranty.

For lighter duty uses it doesn't really matter.
 
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Resurrecting this thread. The book calls for 80w-90 on the Dana 30. I’m about to do my re-gear and for my Dana 44 I have 85w-140 with GL-5. Can I use this weight oil for both the Dana 30 and Dana 44? I’m sticking with conventional.
 
JMT said:
Resurrecting this thread. The book calls for 80w-90 on the Dana 30. I’m about to do my re-gear and for my Dana 44 I have 85w-140 with GL-5. Can I use this weight oil for both the Dana 30 and Dana 44? I’m sticking with conventional.
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Yep
 
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Jerry Bransford said:
Still the same. So long as the gear lube has the GL5 rating, the exact viscosity is not critical. Go with a heavier viscosity like 80W-120, 75W-140, etc. if you tow, or something like a 75W-90, 80W-90 etc. if you don't tow much.
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I plan on changing mine, do you think if I'm gonna tow a small trailer once a week to the town dump I have to go with the heavier viscosity ? I dont do any crazy off roading either...
 
robert_tj_ski said:
I plan on changing mine, do you think if I'm gonna tow a small trailer once a week to the town dump I have to go with the heavier viscosity ? I dont do any crazy off roading either...
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The viscosity is unimportant unless you're getting into extreme uses. From what you say a 75W-90 or 80W-90 would be fine too.
 
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I wish I had taken a photo when I did mine last, but FYI: there is a depression at the bottom of the Dana 30 case (at least on my 04) that holds approximately a cup of oil that won't drain out. I removed the remaining oil by absorbing it with some rags and then cleaned out the grit that had settled at the bottom of the depression.

Given that it's only 1.3 quarts capacity, I felt like it was a good idea to get the remaining fluid out of there.
 
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RMETeeJay said:
I wish I had taken a photo when I did mine last, but FYI: there is a depression at the bottom of the Dana 30 case (at least on my 04) that holds approximately a cup of oil that won't drain out. I removed the remaining oil by absorbing it with some rags and then cleaned out the grit that had settled at the bottom of the depression.

Given that it's only 1.3 quarts capacity, I felt like it was a good idea to get the remaining fluid out of there.
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Do you fill it up until it starts over flowing from the fill plug? I'm planning on taking the whole cover off, inspect the inside and clean inside then put new gasket on and maybe nicer covers.
 
Yes, that is the way to do it. Get a couple of cans of brake cleaner and try to clean the insides as much as possible, then empty the depression and clean it out best you can. Let it air out and then refill up to the fill hole.

If you go with a new cover, it wouldn't hurt to clean the inside too.
 
RMETeeJay said:
Yes, that is the way to do it. Get a couple of cans of brake cleaner and try to clean the insides as much as possible, then empty the depression and clean it out best you can. Let it air out and then refill up to the fill hole.

If you go with a new cover, it wouldn't hurt to clean the inside too.
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Cool thanks !
 
tworley said:
Highly recommend a lube locker gasket. Clean install and no wait-to-dry time before filling the diff.
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You're not supposed to use ANY RTV/Permatex whatever with the lubelockers right? I swear I saw a youtube demo where they guy applied just a little around the cover to help "set" the gasket in place before reattaching the diff cover.

Thanks for the tip @RMETeeJay - I also have an '04 and this is good to know.
 
Not_Invented_Here_ said:
You're not supposed to use ANY RTV/Permatex whatever with the lubelockers right? I swear I saw a youtube demo where they guy applied just a little around the cover to help "set" the gasket in place before reattaching the diff cover.
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Nope. Just place your cover over it (no oil) and torque it down in a star pattern. Well worth the $20-25. Plus you get a cool sticker.
 
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Just to put this out there...

A friend of mine who is a mechanic has access to service manual repairs etc. The alldata.com website for service manual and repairs calls for a synthetic 75w140 for all rubicons (Dana44) front and rear axles.

I don’t know why it isn’t specified on the owners manual. I have the owners manual for my 2004 Rubicon but it doesn’t separate the rubicon’s axle from the rest and the alldata website which collects info from manufacturers does separate it.
 
Jerry Bransford said:
The viscosity is unimportant unless you're getting into extreme uses. From what you say a 75W-90 or 80W-90 would be fine too.
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@Jerry Bransford I'm about to change my TJ front and rear differential fluids and I don't tow or would define my driving as heavy use.. BUT we have some super steep roads here.. like the last 100 meters to my house delivery drivers often refuse to drive up, because its to steep.. would that be defined as heavy use? also we've an average daily temp of 86 degrees. ok if I go all 80W-90 GL-5? or should I use 75w140 synthetic for the rear, or both?
 
Your gears will run cooler if you fill them with a conventional gear lube, and yes it is true that the axle gears do run cooler when lubricated with a conventional gear lube. I'd probably run a 75W-140 or close to that viscosity, the exact viscosity is not critical.

But no, I would not consider that final 100 meters to your house as even close to heavy use. And both axles can run the same gear lube.

But if your rear axle has the Tracloc limited slip differential inside, make sure the gear lube you choose says "compatible with limited slip differentials" on the back label. The Tracloc requires an additive to work properly which is contained in gear lubes that say they are compatible with limited slip differentials. Most already contain the additive so it's not hard to find. And if you don't have a Tracloc in your rear axle, the gear lube can have the additive without causing any problems.
 
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