Differential gear wear at 12.5k miles, is this normal?

Mobusaki

Mobusaki

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Installed by a mechanic 4 years, 12.5k miles ago. Ford 8.8. Proper break in, I've always used 75w-140 conventional, it never ran low. There are lots of fines but no chunks. All the teeth are intact, however the coloration/pattern has me concerned. There is a visible ridge worn into the base of each tooth - not huge but you can feel it with your finger. I've not been able to find any photos on the internet that look like this, particularly of the pinion.

Edit: There are no weird noises when driving. The pinion nut is tight, pinion has no play at the yoke. Has a Truetrac installed at the same time by the same mechanic. He did the front gears as well and they don't look like this.

What do you guys think?

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I know you said Ford8.8 proper break in, but I just want to clarify you changed oil after break in right? Very strange either way for it to not be making noise but see this
 
Yes, and several times since. I've been getting fines the whole time but I read that is normal. I've noticed the ring gear wear but it looked OK to me (compared to the yellow paint patterns I found). I'm not sure if the ridge is new or not, but I noticed it this time. The pinion was that color before but I didn't think anything of it, since I don't know what it should look like. But the pattern, the stripes, I noticed this time and thought maybe it isn't right.
 
Mobusaki said:
Yes, and several times since. I've been getting fines the whole time but I read that is normal. I've noticed the ring gear wear but it looked OK to me (compared to the yellow paint patterns I found). I'm not sure if the ridge is new or not, but I noticed it this time. The pinion was that color before but I didn't think anything of it, since I don't know what it should look like. But the pattern, the stripes, I noticed this time and thought maybe it isn't right.
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You have always gotten fines in both the front and rear or just the front? Can’t say I’ve ever seen fines in a diff properly done
 
Gave the teeth another feel, this time with warm hands and also gently running a flathead across it. Now I can't feel a ridge at all. Maybe my mind was playing tricks on me given how it looks. So perhaps the ring gear is fine? The pinion still looks awful to me - but I'm not sure what it should look like. The photos do make the dark colors and lines look more dramatic because of the flash.

The photo of the pinion gear makes it look rough, but touching it by hand just now it feels smooth.
 
My Dana 30 and Dana 44 with 140k are sitting in my garage and they look a bit like that but I checked for a ridge because I don't know shit about gears. If you don't have a ridge then I might fill and go. Those small flakes in the oil aren't great but I don't think they are going to cook anything else. Besides spider gears and bearings are cheap. Run it until it complains!
 
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pagrey said:
My Dana 30 and Dana 44 with 140k are sitting in my garage and they look a bit like that but I checked for a ridge because I don't know shit about gears. If you don't have a ridge then I might fill and go. Those small flakes in the oil aren't great but I don't think they are going to cook anything else. Besides spider gears and bearings are cheap. Run it until it complains!
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That's what I want to hear! 😆 Your pinion gear looks like mine then? Dark where the pinion teeth contact it?
 
Awesome, thank you! I wasn't able to find a good photo like that of a used pinion gear. That pretty much looks like mine except without the dramatic contrast, some of which is due to my flash. I'm feeling better about my gears now. 😀
 
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It's easy to get worked up about gears since most of us don't know what to look for and it's such a big investment as far as mods go.

I had a set fail in 2000 miles, they were howling like a banshee while I drove them 300 miles back home and they didn't look any different to me than the gears I have now.
 
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freedom_in_4low said:
It's easy to get worked up about gears since most of us don't know what to look for and it's such a big investment as far as mods go.

I had a set fail in 2000 miles, they were howling like a banshee while I drove them 300 miles back home and they didn't look any different to me than the gears I have now.
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After my regear, mechanic showed me my 3.07 pinion, teeth were pretty much rounded. Also pointed at the rag with all the metal shaving they cleaned out of the tubes.
He said he could not imagine how much howling i had to put up with before i brought it to him. I was confused for a second :unsure:, told him that i had no idea there was anything wrong with it to begin with, i simply fed up with stalling at red lights and standing on the gas pedal at highway speeds.
While driving back i thought to myself "hell yah, amsoil gear oil is so bad ass, even efed up gears cant say shit" , ordered 6 more quarts when i got back 😅
 
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If your concerned about it, have a shop check the backlash and run a contact pattern. Its quick and easy and it'll show if anything is failing. As long as your not getting any howling, or grinding, or any kind of feedback from the gears, why worry about it though.
 
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L0jik said:
If your concerned about it, have a shop check the backlash and run a contact pattern. Its quick and easy and it'll show if anything is failing. As long as your not getting any howling, or grinding, or any kind of feedback from the gears, why worry about it though.
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You're right. I think I'll even give that a go myself. I've been wanting to learn this stuff (gearing is the only thing I've had someone else do on my Jeep). Checking the backlash and pattern would be a good place to start.
 
eastbloc said:
After my regear, mechanic showed me my 3.07 pinion, teeth were pretty much rounded. Also pointed at the rag with all the metal shaving they cleaned out of the tubes.
He said he could not imagine how much howling i had to put up with before i brought it to him. I was confused for a second :unsure:, told him that i had no idea there was anything wrong with it to begin with, i simply fed up with stalling at red lights and standing on the gas pedal at highway speeds.
While driving back i thought to myself "hell yah, amsoil gear oil is so bad ass, even efed up gears cant say shit" , ordered 6 more quarts when i got back 😅
Click to expand...

I'll have to try Amsoil next time if they have the oil I need. I've heard nothing but good things about their products. My needs are a bit specific though due to the Truetracs. Eatons says to use a conventional oil without LSD additives. Well, most oils include them! This time I'm using Valvoline Heavy Duty conventional, which was one of the few I could find that clearly says there are no friction modifiers for LSDs added. I'm hoping the TT's work a bit better now, since the stuff I used before likely had some additive already.

BTW, if the shavings I find in both diffs is atypical, perhaps that could be from the Truetracs? It's a closed unit unfortunately so I can't inspect the gears by just taking off the diff cover. :(
 
Mobusaki said:
I'll have to try Amsoil next time if they have the oil I need. I've heard nothing but good things about their products. My needs are a bit specific though due to the Truetracs. Eatons says to use a conventional oil without LSD additives. Well, most oils include them! This time I'm using Valvoline Heavy Duty conventional, which was one of the few I could find that clearly says there are no friction modifiers for LSDs added. I'm hoping the TT's work a bit better now, since the stuff I used before likely had some additive already.

BTW, if the shavings I find in both diffs is atypical, perhaps that could be from the Truetracs? It's a closed unit unfortunately so I can't inspect the gears by just taking off the diff cover. :(
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Jack your rear end up and rotate the tires… there should be a ~2” hole in the truetrac where you can view the gears. At least was in the one I installed in my Silverado a handful of years back
 
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