Leaky Rear Axle Bearing

[NightFlyer321]

1991 k2500 5.7
Was checking the rear drums today and noticed quite a bit of goop of the back of the wheel hub. Is this something that should be addressed right away or what? Diff fluid and gasket were replaced about two months ago, if that matters at all.

You must be registered for see images attach

You must be registered for see images attach

 

[xXxPARAGONxXx]

Well, that didn't happen overnight. So, no, it doesn't require an emergency repair, especially if you recently refilled the gear oil in the rear axle.

It's a leaking rear axle shaft seal. The photo suggests it is still actively leaking, so plan on replacing the seal sooner than later. Unfortunately, you will have to remove the differential cover to remove the rear axle shaft lock from the differential to remove the rear axle shaft from the axle housing.

 

[RichLo]

^ Yep agree'd.

Leaky axle stuff generally doesnt need emergency repairs unless its like a diff cover gasket failure that will drain the whole thing just sitting there.

As long as you know about the problem and keep it topped off you can let axle seals and pinion seal go until you have the time/money to fix it properly. I would recommend getting a new fill plug right away though if you plan on topping it off regularly.

 

[Schurkey]

Worst-case scenario: The axle seal is leaking because the axle shaft bearing is wiped-out. The bearing has dug a groove in the axle shaft, and now the axle shaft isn't centered in the seal.

With a groove in the axle shaft, that shaft now has a stress-riser that can lead to Sudden Terminal Disassembly (STD). You'd know when that corner of the truck drops to the pavement with a shower of sparks, and your tire, wheel, brake drum and axle-shaft flange passes you.

Not-quite the worst-case scenario: The seal has worn a groove into the axle shaft. A new seal--by itself--may or may not fix the leak. A new seal positioned so the seal lips ride on a non-worn part of the shaft may seal the leak.

Or you may be unlucky like me, and the axle shaft has to be replaced to get rid of the worn area so a new seal isn't riding on a damaged shaft.

This axle shaft had to be replaced because the seal wouldn't stop seeping.

You must be registered for see images attach

 

[NightFlyer321]

Well, that didn't happen overnight. So, no, it doesn't require an emergency repair, especially if you recently refilled the gear oil in the rear axle.

It's a leaking rear axle shaft seal. The photo suggests it is still actively leaking, so plan on replacing the seal sooner than later. Unfortunately, you will have to remove the differential cover to remove the rear axle shaft lock from the differential to remove the rear axle shaft from the axle housing.

You're right about it not happening overnight. When I changed the diff fluid, there was plenty in there and that was probably the first time it had been done in 15 years. (although the truck was sitting for 10 of those years)

 

[Erik the Awful]

Catch that fresh gear oil in a pan, screen it, and put it back in once the repair is done. That $#!+'s expensive.