What is causing Diff fluid to leak from my Knuckles

[joshthemule]

History: months ago, I leaked some diff fluid from the driver side knuckle. At the same time, I had a problem with my hub on the same side not disengaging. I took the hub apart and fixed that problem and also the leak with away.

This weekend, I replaced my stock diff cover with a Rock Crusher cover (I think the fill plug might be a bit higher than stock) and now the leak is coming from the passenger side. Also, I found that the passenger side hub is not disengaging now. How are these things related and what is causing the leak?

[trkklr77]

you axle shaft seals are shot. 100% tear down.

[joshthemule]

Wow, If I'm not replacing everything, then do I still have to worry about gear set up or can I just reassemble and check the backlash?

[florida4x4]

water in the housing can raise the oil level to where they leak regardless. Check your vent tube and fluid level. Overfilling and a bad vent can cause this problem too.

You can pull he carrier without messing up the setup. Just be sure to keep things spotless clean when you reassemble. checking the backlash is always a good idea after an operation like this.

[brooks294x4]

you dont have to take the pinion out, so as long as your not moving the shims, you should be ok, im in the process of redoing my D60 now and the inner axle seals will be goin in in the next 2-3 days

[joshthemule]

Originally Posted by florida4x4

water in the housing can raise the oil level to where they leak regardless. Check your vent tube and fluid level. Overfilling and a bad vent can cause this problem too.

You can pull he carrier without messing up the setup. Just be sure to keep things spotless clean when you reassemble. checking the backlash is always a good idea after an operation like this.

Well, like I said, I think the capacity may have increased with the new fill plug location. I'm going to research and find the exact fluid capacity and fill it, then see if it leaks.

thanks for the input

[Mechanos]

Also, like mentioned above.... check your vent to make sure it's not plugged. As heat builds in the diff, the oil will expand and build up pressure forcing the oil out the seals if the vent is plugged and cannot relieve the pressure.

[joshthemule]

Originally Posted by Mechanos

Also, like mentioned above.... check your vent to make sure it's not plugged. As heat builds in the diff, the oil will expand and build up pressure forcing the oil out the seals if the vent is plugged and cannot relieve the pressure.

very good suggestion. Thank you

[Grumpy_old_fart]

While youre there, clean out the axle tubes. they are probably full of shit, anyway. if you push the axleshaft back into the diff, its going to push a bunch of dirt and shit with it, contaminating the oil, and getting sharp debris on your new axle seals... good way to ruin em.

[GMCTruxrule]

Originally Posted by joshthemule

Also, I found that the passenger side hub is not disengaging now. How are these things related and what is causing the leak?

The fact that both problems are on the same side of the truck is convenient, but not in any way related.

Axle seal is responsible for your leak.

Why the hub won't disengage could be due to a dirt and mud in your hub, (faulty seals, lack of maintenance) or broken parts.

But it will all require disassembly to figure it out. Better get busy.

[JGVABronco78]

Some quick advice.
1. Check the vent first, and see if it was clogged, fix if necessary.
2. Assuming the vent is ok, before you raised the oil level, and before when it wasn't leaking, the oil level was probably alright where it was, which was at a point where it leaked down through the bad seals. If the bearings and gears still look alright, its fine to let it leak down to this point again and don't worry about it.
3. However, if you plan on dunking it in mud or water, or if you do, you should take it down and fix the seals so you don't contaminate the diff fluid.
4. If you do clean out the tubes, take the diff out first and plug the holes good so you don't contaminate it.
5. Check the axle shafts real good. If they are scored or heavily worn and reduced size, new seals will not keep it from leaking, and the axles will need replaced or sleeved if they still offer those kits.