Clotted axle gear oil

[hike]

Adding ECO HUBS to our M1078 this weekend is going well except the front axle gear oil is clotted. Not cloudy or milky, black as midnight, clots when cleaning out the wheel hub with metal cleaner. It was difficult to clean out the wheel housings sufficiently. Planning to drop all the gear oil out and at least changing it all again after 500? miles. I recall my dad running kerosene in gunky things for a bit, is that a good idea?







I haven't wiped off the other two from the rear axle. Bearings look good, surfaces of the reduction gears look good, not much metal on the magnet at the wheel hub.

Rear axle gear lube is brown and looked really good, just the front looks nasty.

Please share your thoughts—

 

[Ronmar]

How does the front center diff fluid look? The front is 3 different reservoirs 2 hubs and center axle, with the vents tied together but they should never share any fluid… you should drain the center diff fluid and inspect it at the very least…

this almost looks like some motor-pool maniac greased all 4 bearings then re-assembled it and added oil to the hubs which then mixed/reacted with the grease… The inner bearings are greased, the outer bearings are wet lubed along with the spider gears… y0u should pull the outer bearing to throughly flush the crud out of it…

 

[Keith Knight]

I agree with ronmar, it looks like grease mixed with gear oil.

 

[hike]

After I posted this while finishing the front passenger hub up I had the same thought: someone packed the bearings.

I didn't pull the bearings, though I blew through my metal cleaner stash until the bearings ran out clean. I'll drop the center Monday, refill all three and redo in 250 - 500 miles. If it is still looking fugly, I'll pull the hubs.

Thank you. It is nice to have consensus—

 

[hike]

Interestingly, in the 1,500 miles or so I have driven, her by the back of hand test, the front hubs have felt cooler than the rears—

 

[GeneralDisorder]

After I posted this while finishing the front passenger hub up I had the same thought: someone packed the bearings.

I didn't pulle the bearings, though I blew through my metal cleaner stash until the bearings ran out clean. I'll drop the center Monday, refill all three and redo in 250 - 500 miles. If it is still looking fugly, I'll pull the hubs.

Thank you. It is nice to have consensus—

Pull the bearings. You now have grease/gear oil/brake cleaner contamination down in the CTIS seal areas of the hubs and there's plenty of crap still in there beyond the bearings that you will never get out with an aerosol can. Not a great way to button it up. Pull it all off and clean it properly.

Interestingly, in the 1,500 miles or so I have driven, her by the back of hand test, the front hubs have felt cooler than the rears—

That's normal since the front hubs don't share gear oil with the ring and pinion. All of these trucks run like that all the time. ECO hubs reduce temps considerable but the rear will still be hotter due to the gear oil being heated by the ring and pinion.

 

[hike]

Pull the bearings. You now have grease/gear oil/brake cleaner contamination down in the CTIS seal areas of the hubs and there's plenty of crap still in there beyond the bearings that you will never get out with an aerosol can. Not a great way to button it up. Pull it all off and clean it properly.

I have been pondering this since watching @Xengineguy installation video. As it is we have gear oil/brake cleaner contamination in the rears and gear/oil/brake cleaner/grease in the fronts. What is the proper way to clean it?

 

[GeneralDisorder]

I have been pondering this since watching @Xengineguy installation video. As it is we have gear oil/brake cleaner contamination in the rears and gear/oil/brake cleaner/grease in the fronts. What is the proper way to clean it?

The right way to do it is to pull the hubs (after removing wheels and drums), clean everything thoroughly and replace all the hub seals and the CTIS seals and backing rings, repack the inner bearings with new grease, and set the bearing preload, etc. Technically the military originally specified this as an annual service although now it's just an inspection. But at the very least it's something that should be done every 5-10 years depending on operating conditions. If the CTIS seals fail in the rear it will force all the gear oil out of the breather and run the differential dry of gear oil causing pretty ugly, unrecoverable, and catastrophic failure usually requiring replacement of the entire axle assembly.

I've done four ECO hub installs and only on one of those did we do the ECO hubs without a full seal replacement and bearing repack.

 

[hike]

The right way to do it is to pull the hubs (after removing wheels and drums), clean everything thoroughly and replace all the hub seals and the CTIS seals and backing rings, repack the inner bearings with new grease, and set the bearing preload, etc. Technically the military originally specified this as an annual service although now it's just an inspection. But at the very least it's something that should be done every 5-10 years depending on operating conditions. If the CTIS seals fail in the rear it will force all the gear oil out of the breather and run the differential dry of gear oil causing pretty ugly, unrecoverable, and catastrophic failure usually requiring replacement of the entire axle assembly.

I've done four ECO hub installs and only on one of those did we do the ECO hubs without a full seal replacement and bearing repack.

Good advice. I'll order the seals and add to my cab and chassis plan. Thank you—