Ring gear wear (1 Viewer)

[Eurasiaoverland]

I recently purchased a used differential (37:9 LSD). This has spent its life as a rear diff. Given that my front diff was practically unused (the car never went off road), I plant to switch the ring gear and pinion from my front, open diff on to the LSD and install in the rear. The plan was to put the worn ring gear/pinion onthe front, open diff.

The ring gear and pinion have no damage, as far as chips or broken teeth are concerned, but I notice some unusual wear patterns in the drive (convex) side of the ring gear teeth:

The drive side of the ring gear teeth is textured from wear.

What is the cause of this wear? Is it normal high-mileage wear? Or does it indicate poor setup?

The coast sides of the ring gear teeth show mild wear, but still feel smooth to the finger.

The pinion gear does not have any unusual wear (to my eye).

Is this junk? Will it always be noisy or have a short life expectancy? My plan was to install this ring gear and pinion on the front axle, so by my understanding this effectively reverses the gear sides with drive becoming the concave face and coast becoming the (worn) convex face, which might limit future wear, if my thinking is correct.

Interested to hear more experienced opinions than mine.

EO

 

[Spike Strip]

Looks like low-oil or long-time-no-change-lubricant wear... Probably going to be noisy, but probably OK for a front - but I don't have a whole lot of experience using parts like that.

 

[Eurasiaoverland]

Looks like low-oil or long-time-no-change-lubricant wear... Probably going to be noisy, but probably OK for a front - but I don't have a whole lot of experience using parts like that.

This was bought used here in SE Asia so wear from having never changed the oil is very possible!

 

[Spike Strip]

The more I look at the spalling on those gears the more I think it's already through the hardened outer skin, making the ring prone to failure. I wouldn't worry about running it as a front diff around Los Angeles , but since you're planning more remote tours (but probably less dangerous than L.A), you might want to not regret it later and look for a replacement or a new ring gear...

Hopefully someone with more experience in Differentials will chime in.

 

[cruisermatt]

That looks like normal high mileage gears. I’d have no concern with using it in a front with locking hubs where it won’t see high speeds or loads.

And ZERO chance you’d hear it over your diesel.

 

[lacalvette]

Bear in mind that these gear when used on low pinion rear end works on the drive side.
When used in front (low pinion) it works on coarse side. ( Front low pinion push on coarse side of the ring gear when going forward)

So if you used those gear in the front, going forward in 4x4 it will used the « un wear » part of the ring gear (coarse)

You may have a look at the 4 small pinion gear teeth surface, mine shows sign of wear (now installed in front diff) my LSD rear diff made noise, whine started at about 90km/h. Well I hope it was it tho!

Edit: Not sure only the teeth surface are hardened, I would think the whole ring is. On modern industrial application, the pinion, which work harder than the ring gear, is harder than the ring gear.
May try to file the ring gear at different location to see if these is difference in hardened area.

Coarse side seem to show some corrosion? (Water ingress?) drive side looks like gears been in contact some time? Bad viscosity?
I think too it would be alright in front.

 

[lacalvette]

You can also use your third member from your actual rear semi-float in the front diff.
Just swap the LSD in your actual front third member. No need to remove your pinion (if bearing are good) and use your « front » side carrier bearing on to the LSD. Chance that you only need to adjust side carrier bearing preload ,backlash (like it was) and run a gear pattern