10.25 Sterling, How Bad is too Bad

[DougBoy66]

I popped the dif cover off last night and there was a fairly thick sludge layer ad the bottom but it didn't look like it had any debris in it. Looked more milk shake like, like it had some water intrusion at some point. I sprayed everything out with parts cleaner cleaning out all the gunk in the corners and crevices. Some history here, I have no Idea how this truck was maintained other than what evidence I uncover. Looks like it had regular maintenance done. It had a gooseneck ball so I know it worked in it life of 400k plus mile.
So the pinion doesn't have any noticeable side or end play but it is pretty sloppy rotationally ( in my opinion). The ring and pinion don't look like there is any severe wear or broken teeth. But the worrisome part I drug magnet through the oil and it looked like a Wooly Willie game

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So my question to you all- How much can I damage it if I just clean it up, new oil and the cover I am installing has a magnetic drain so I can drain and refill easily. I know the correct answer is to rebuild it, I have plans to do that but I just wasn't expecting to do so right now.
I wasn't having issues or leaks before opening it up and finding this, I was just replacing the cover when I made this discovery. It is not a truck that I am going to drive everyday but I do want to be able to go places lol.

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[The_Josh_Bear]

What does sloppy rotationally mean? Like when you turn the pinion forward and reverse it has a lot of null zone? (Time that it's not engaging the ring)
I've been really impressed with how stout a 10.25 is under normal use. I had a pinion nut work loose on me in my younger years and drove it a while before finally getting to it. Talked to an old grey beard at a drivetrain shop and he said 90% of the time you can just tighten up the nut and it'll be fine again until the truck falls apart around the axle, lol. I don't remember the spec, but let's pretend it was 500 ft-lbs. I didn't have a way to measure that so I put 100lbs on a 5ft bar. 5x100=500. The hardest part is keeping the torque from moving the truck. You can jam a heavy rag inside the gearset if you need to do the same, plus parking brakes.
I drove on that axle with no issues for 6 or so years with no more issues, noise, or shavings.

The real problems arise when you have bearing damage, then it's for sure time to rebuild. It's possible to have gear damage, but outside of crazy shock-load the gears will only break *after* the bearings go tango-unicorn.

Also, that gear oil is nasty dark! Maybe it had moly in it? Or maybe a great time to change it! I love my Schaeffer oil in the axles, but the moly makes it stupid dark. You always feel like it's burnt up or something.

TL;DR I'd make sure the pinion nut is tight, fresh high quality oil, and send it.

 

[DougBoy66]

What does sloppy rotationally mean? Like when you turn the pinion forward and reverse it has a lot of null zone?

Yes sir. Not noon to 1 o'clock, maybe half of that

I'd make sure the pinion nut is tight, fresh high quality oil, and send it

I think the bearings are ok, no rough feel rotating them and everything looks to be as they were made. No missing parts and no big metal in the oil. Only "dust" for lack of a better word. I was leaning towards cleaning it up and lubing it up and rolling with it. It had no issues before so I will just be mindful of it and thighten the pinion nut. Thank you for the input and advice

 

[IDIBRONCO]

It's been a while since I've checked mine. I probably have more than that amount of free play in mine. I just learned to be smooth on my shifting and I keep driving the truck. In other words, I'll usually let the clutch pedal out all the way before I step back on the throttle again. One day, I should change the diff oil again, but not today.

 

[ROCK HARVEY]

I would run it. When I bought my truck I found glitter and a chipped pinion tooth in the rear end. I kept driving it while I looked on FB marketplace for a good price on a used rear end. I got a year out of it and probably could have gone longer, but I eventually found a cheap used rear axle and swapped it in.

 

[u2slow]

I would run it too.

And start shopping for an extra $100-200 diff to start rebuilding on the side.

 

[The_Josh_Bear]

@DougBoy66 why is there plastic wrap on the tires in your avatar picture? I keep wondering and forgetting to ask.

 

[IDIBRONCO]

Looks like a mock up picture to me.

 

[DougBoy66]

You are exactly correct IDIBRONCO! Josh_Bear they are still wrapped in plastic because I just pulled them off the delivery truck and put them in front of the truck to see how they looked but I had to leave the wrap on them incase I had to send them back

 

[DougBoy66]

Put it all back together. Fresh gear oil and the new cover that has a drain plug so it is a little more service friendly. Thank to everybody that had input for me. I thought I was good to go, but it is good to hear some confirmation that it is

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[The_Josh_Bear]

That's a dang s e x y rear end right there!

 

[MtnHaul]

Which disc brake conversion kit did you go with? Any issues?

 

[DougBoy66]

Thank Josh! MtnHaul I ordered the Ruff Stuff kit through Complete Preformance. It bolted right up no issues. It is for single rear wheel only though. It comes with weld on brackets for the brake lines but I made some that I could clamp on. You have to cut and reflare the hard lines. If I where doing it again you can upgrade to calipers that have the E-Brake built in.

 

[MtnHaul]

Yeah RuffStuff makes some nice parts. I know they mention something about some 10.25 axles needing a spacer while others don't but it sounds like yours was straightforward.

 

[DougBoy66]

. I know they mention something about some 10.25 axles needing a spacer while others don't but it sounds like yours was straightforward.

The spacers are hit and miss on the 10.25. Some need them and some don't but the are included so you would have them either way. I ended up needing to use them. One thing was I needed to get some longer grade 8 bolts. Other wise the bolts from the drums would have worked. Only thing I have an issue with is the banjo bolts. I think the are a bit short so I am afraid of them stripping out before they are tight enough