Gear oil question

For my rear diff I have nitro 4.56 gears with an arb air locker. Air locker is notorious for leaking oil thru the air lines and out the fittings. I've been told to use something thicker to help the leaking. its not a lot I monitor it daily but I see it around the diff. any recommendation's?

 

Lucas 85W/140, Its all I run and is what ECGS recommends.

$35 Lucas Oil 10045 Heavy Duty SAE 85W-140 Gear Oil - 1 Gallon

https://www.amazon.com/Lucas-10045-...qid=1699538213&sprefix=lucas+85,aps,90&sr=8-2

 

My rear arb was leaking gear oil up the lines. I just recently replaced the seals as well as upgraded to the newer design bulkhead with the pneumatic fittings. The old copper air line was basically crimped at the old style bulkhead which I believe was allowing gear oil to make its way to the air line.

I also added ARB’s in-line back pressure piece. Will see if it returns.

Either way I put 80w90 in currently. I believe 85w140 was in it before and didn’t make a difference, that bitch was leaking no matter what.

 

Don't run a different viscosity fluid in an attempt to stop a leak. The fluid is there for the gears, run what the MFR recommends. Not to mention that a thicker fluid will probably have zero effect on an air leak.

 

I used 85w/140 in my front differential and it puked gear oil up and out of the breather.
Some say it was due to being "over" filled. But I did just as I have every other differential.
Filled it up until it just started running out of the fill hole. Took the plug out and "topped it off" after it leaked.
And it did it again. I just let it puke it out and called it good after that....
Seems to be happy with what ever amount is in there now.

The only reason I even mention this is because you say other oils (thinner) will leak out the lines.
Well, thicker can too.

 

I had the exact thing happen.

 

Speaking of 85/140, I have 4 qts (new) I can sell relatively cheap since I don't need them any more.

 

I wonder if there's any designed parts solutions that can address this, like a one way valve, mesh strainer screen, routing a certain way, etc.

I've heard this is pretty normal, happens on all of them, and that the "solution" is to periodically activate it for air to push gear oil back into the diff, rather than leaving it off for really long if you don't use it a lot.

I believe Toyota says to put the truck (stock) in 4x4 at least once a month on loose surface; potentally even 4LO for x amount of miles as maintenance
maybe that's for the actuators or whatever they're called

if engaging air does work for this, I wonder if that's just something to add to that "monthly maintenance list"

I'm on stock diffs mech LSD and have had no issue with synthetic 75w140 besides maybe somewhat reduced MPG
have heard plenty of gear companies recommend thicker oils