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Ford 8.8 ring gear bolts fell out...now what?

Muddy Beast

NAXJA Forum User
Location
WA
Well last night I was on the freeway when a noise started, it sounded like rubbing/thunking on something that moves as it's frequency varied with speed. I carefully drove it home after an external inspection of everything it could have been that's easy to get to with no avail. Took the rear diff cover off today to find the ring gear bolts fell out. My rear axle was built not quite 2 years ago at a shop, I've changed the fluid maybe 4-5 times since having the axle built and never saw any issues arise overtime. So far I know for sure 4 bolts fell out, all 4 right next to each other. One bolt found its way between the carrier and the ring gear, the other three dropped out gnarled up. The only other bolt I can see that holds the ring gear is working it's way out and is about halfway out.

Ford 8.8 31 spline, 4.88 gears, stock LSD.

Is this something as simple as me just buying new bolts and throwing them in? Or could I be in for more hurt by not having the diff. pulled and inspected a little more thoroughly?

I took pics, just having trouble getting them on my computer.
 
clean threads on bolts and ring gear very very well and loctite red
 
Sounds as though the ring gear bolts were not torqued properly.
If it were me I wouldn't reinstall new bolts without doing an inspection on both the R&P teeth.
If the bolts were gnarled up as you described then there is a chance of damage to the R&P teeth.
There is probably metallic particles in the gearlube. You should spray out the inside of the case, carrier and R&P with brake cleaner to remove as much as possible.
If after the inspection of the R&P you are satisfied with their condition; I would ensure the ring gear bolts are torqued properly. Might not be a bad idea to apply a little loctite to the threads.
 
There are definitely metal chunks floating around in the case now.

Seems as though the teeth are OK though.
 
Whatever gnarled up your bolts would have got gnarled up in the process.
You don't get metal shavings without breakin shit... look closer.
 
Whatever gnarled up your bolts would have got gnarled up in the process.
You don't get metal shavings without breakin shit... look closer.

What do you know about steel?

Not trying to sound like a jerk, but hardened steel can very easily destroy bolts without a scratch.

But yeah I agree, I need to go over everything.
 
Like everybody else said, clean it out, new bolts with red loctite and before you put the cover on, put a strong magnet in the deep crevis at the bottom that the 8.8 has. I'd pull the cover off a few times after milage to clean off the magnet and inspect.
 
Plus you need to find out why the bolts backed out.Ive seen this happen several times w/ the 8.8,I would check the carrier/ring gear for run-out.
 
I would look into safety wiring the ring gear bolts in place, as well as loctite. Definitely check the carrier for runout and the teeth on the gears for damage, run a pattern in a few spots on the ring gear as well. There is a good chance the ring gear is now worn strangely where the bolts came loose.
 
Pinion gear is chewed up, ring gear has some odd wear as well. Case is toast. I put new bolts in with red loctite and reapplied loctite to the remaining bolts (all of them were loose) and she drives OK. But when I let off the gas I get a grinding noise, and it gets louder as I go faster (obviously)...it's pretty annoying even when cruising around the local roads, I have to put the Jeep in neutral whenever I coast but even then I still get a pretty audible noise.

Now the question is, what caused this? I had a shop set up the gears a little less than 2 years ago. I've had a minor DL vibration in some situations, but I would make it go away by hitting the gas to get into a different gear. And most recently my rear tires are partially out of balance (put them on about 2 months ago).
 
Scott, with your grinding noise, I would suspect bearings. But since everything grenaded on you, I would have someone check your run out also.
 
Scott, with your grinding noise, I would suspect bearings. But since everything grenaded on you, I would have someone check your run out also.

Honestly I'm more suspecting that the pinion gear was deformed on the back end of the gears, so when they aren't being powered the ring gear rubs the opposite side of the pinion gear and makes the noise. It's very consistent, and just doesn't quite feel/sound like a bearing.

As far as the gears, they were Superior (I believe) and the shop was Auburn Car Repair and Offroad...but my understanding is they had someone else do the actual gear install.
 
Honestly I'm more suspecting that the pinion gear was deformed on the back end of the gears, so when they aren't being powered the ring gear rubs the opposite side of the pinion gear and makes the noise. It's very consistent, and just doesn't quite feel/sound like a bearing.

As far as the gears, they were Superior (I believe) and the shop was Auburn Car Repair and Offroad...but my understanding is they had someone else do the actual gear install.

What you're describing is a coast noise. It's usually because the backlash is excessive, which could be the case since the ring came loose and was wonky, but it is also possible when the pinion bearings are bad, or any number of issues.

Doing a pattern check was a very good suggestion made above.

Auburn is a member here yes? I would contact them and see if they're willing to work with you on at least a partial credit to have the gears setup again. It's hard to ask them to do the setup again 2 years later. I would call them and see if they're willing to help you out.
 
What do you know about steel?

Not trying to sound like a jerk, but hardened steel can very easily destroy bolts without a scratch.

But yeah I agree, I need to go over everything.

Not to make you sound like a jerk, but every diff I've seen that had bolt-sized bits floating around in it has a chewed up carrier, broken teeth, etc.

Tell ya what, when you fix your diff we'll toss a few carrier bolts in there and run it for a little while. If the awesomeness of the hardened steel parts destroy the bolts without a scratch on the carrier/R&P, I'll buy you new tires.
 
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Scott,

If i were you I would call John at ACRO and see what he is willing to do for ya. I personally think that they company/ Person who did the initial install should eat the cost of a whole new set up, I.E. Gear set, Bearings, etc.

But thats me i cant see that it was a product failure. I would look for some sort of compensation, nothing big, but at least the cost of new parts and housing.

Like I said thats just me.

Good luck Scott.
 
Not to make you sound like a jerk, but every diff I've seen that had bolt-sized bits floating around in it has a chewed up carrier, broken teeth, etc.

Tell ya what, when you fix your diff we'll toss a few carrier bolts in there and run it for a little while. If the awesomeness of the hardened steel parts destroy the bolts without a scratch on the carrier/R&P, I'll buy you new tires.

It all depends. In this case my carrier was effected, but if a bolt didn't get between the carrier and ring gear everything SHOULD have been fine. As the only damage I could find was resulting from that.

Obviously long term anything floating around that shouldn't be would do something, I was more referring to the short term effects being a toss up for damage.

Scott,

If i were you I would call John at ACRO and see what he is willing to do for ya. I personally think that they company/ Person who did the initial install should eat the cost of a whole new set up, I.E. Gear set, Bearings, etc.

But thats me i cant see that it was a product failure. I would look for some sort of compensation, nothing big, but at least the cost of new parts and housing.

Like I said thats just me.

Good luck Scott.

John is already working with me to find a suitable locker to replace my carrier, as far as labor/gears/etc. I'm not sure yet. I'll cross that bridge when I get there.
 
John is already working with me to find a suitable locker to replace my carrier, as far as labor/gears/etc. I'm not sure yet. I'll cross that bridge when I get there.

That tells me a lot that john is there to help you out, Instead of telling you there is nothing that he can do for ya. :thumbup: to you John!
 
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