What is a Locking Differential? Lockers Explained

[RMETeeJay]

I thought most with the Dana 30 kept the 27 spline shafts even after the locker and 35s.

I'm still not clear on when/why to replace axle shafts during a regear. @Chris indicated that it makes no sense to stay with 27 spline axles with 31s. And for my Dana 44, is it recommended to replace the axle shafts with 31s?

I've since spoken to several garages. One of them recommended installing axle tube seals to prevent water/grime from getting onto the axle seals. Even though I'm not planning on deep crossings, it sounds like a good idea from a longevity standpoint. Does anyone here have experience with them?

 

[EzPeezy]

It makes a lot of sense to stay with 27 splines, even when adding a locker and regearing. That lets you keep your stock shafts to use as replacements in case the upgraded shafts break. I installed ten factory shafts about 7 years ago and havent had any problems. If I broke a shaft it would probably be a real pain in the ass to find a spare with 30 splines in the desert.

I've since spoken to several garages. One of them recommended installing axle tube seals to prevent water/grime from getting onto the axle seals. Even though I'm not planning on deep crossings, it sounds like a good idea from a longevity standpoint. Does anyone here have experience with them?

I have them on my front end and I'm glad they're there to keep the majority of debris and water out. People will tell you that the outer seals can 'hide' an inner seal leak to the point where you won't see it until your diff is empty. That's super stupid and not true. A leak will not be held back by the outer seals that is simply pressed in to the end of the tube.

 

[Chris]

One of them recommended installing axle tube seals to prevent water/grime from getting onto the axle seals. Even though I'm not planning on deep crossings, it sounds like a good idea from a longevity standpoint. Does anyone here have experience with them?

Scam alert! Those "axle tube seals" do you more harm than good. They DO NOT keep water out, and the water they let in, the trap in there, thus causing rust.

If you're going to be crossing through water to the point where the axles are submerged, you're going to have some serious long term problems, I can assure you of that.

 

[Westtown Willy]

It makes a lot of sense to stay with 27 splines, even when adding a locker and regearing. That lets you keep your stock shafts to use as replacements in case the upgraded shafts break. I installed ten factory shafts about 7 years ago and havent had any problems. If I broke a shaft it would probably be a real pain in the ass to find a spare with 30 splines in the desert.

makes more sense to me to strengthen the shaft from 27 to 30 spline to reduce the likelihood of needing to find a spare in the desert to begin with... I understand planning for the worst case scenario but not by increasing the odds that it will occur by intentionally putting in weaker parts.

If someone is that concerned about a middle of nowhere swap of parts maybe bringing those parts along is a better practice than relying on finding them on the fly, even brand new rear axle shafts are as cheap as dirt at around $100 per shaft

https://www.extremeterrain.com/g2-Dana 35-axle-driver-30-yj-tj-9520492301.html

I thought most with the Dana 30 kept the 27 spline shafts even after the locker and 35s.

that does seem to be the case with the front axle. For a lot of reasons repeated here often. I may be one of the few freaks that actually put 30s up there too, overkill no doubt for my uses, but what the hell...

 

[EzPeezy]

makes more sense to me to strengthen the shaft from 27 to 30 spline to reduce the likelihood of needing to find a spare in the desert to begin with... I understand planning for the worst case scenario but not by increasing the odds that it will occur by intentionally putting in weaker parts.

If someone is that concerned about a middle of nowhere swap of parts maybe bringing those parts along is a better practice than relying on finding them on the fly, even brand new rear axle shafts are as cheap as dirt at around $100 per shaft

https://www.extremeterrain.com/g2-Dana 35-axle-driver-30-yj-tj-9520492301.html


that does seem to be the case with the front axle. For a lot of reasons repeated here often. I may be one of the few freaks that actually put 30s up there too, overkill no doubt for my uses, but what the hell...

I'm saying that the REASON to stay with 27 spline is to save money versus buying something that you don't need. You buy a heavy duty shaft kit for the front end, which is usually all you need to do to protect the axle. You now have spares that you can take with you in case you need them, OR you can pull a replacement from almost any jeep front end of this generation that you can find in a junk yard world wide. I assume that a 27 spline versus 30 spline is similar in cost for probably not a lot of benefit. Now if you buy the 30 spline and you want a backup set guess what? You have to buy them twice now to have redundancy for a part that probably wouldn't blow up if it had 3 less splines. You'll also need new unit bearings to run the 30 spline shafts.

And yeah, obviously rear shafts are cheaper than fronts. Apples and oranges.

 

[jjvw]

A question I would ask is how common it is to break a Dana 30 27 spline cromoly axle shaft after lockers and 35s. It doesn't feel very common.

 

[RMETeeJay]

OK, it sounds like I don’t need to replace my axles or use axle tube seals during a regear. What else besides what comes in a re-gear master install kit should be done?