2022 GT - Loose Washer on driver side Rear differential carrier bolt?

[Highvolts]

Hi Folks,

When driving next to other vehicles or walls, I could hear a slight rattle. Hitting bumps, the same. Tonight I got the car up on jack stands and started tapping with a rubber mallet all under the car. As I got toward the back, I could hear it lightly. Finally, I narrowed it to the washer on the rear differential carrier bolt.

The bolt is extremely tight, but is not holding the washer tight. The passenger side bolt I'm able to loosen and torque back down. But not the driver side. I'm afraid of breaking the bolt off. I really think the assembly plant cross threaded the carrier hole.

I am planning to call the dealer, I'm still under the 5year power train warranty. But thought I'd post here.

Anyone seen this before?

here is a video too:

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[Paul McWhiskey]

That is a bummer. Because it is still under warranty I would take it back to the dealer. However, you can be sure that they are going to try and tighten the bolt and call it good.

I would try to work out with them that you can be present when they remove the bolt to determine if it is in fact cross threaded. If so, then they would need to tap the diff or , better yet, helicoil the diff to repair it. Most important is to not allow them to tighten it just enough to stop the washer from rattling. That would only kick the can down the road leaving it to be dealt with at a later date.

 

[WD Pro]

Anyone seen this before?

Yes, I found mine sooner than you, but a bit late for a better outcome ...

Expand the post to see the pics, or click my name in the quote to take you to the source)

Following on from the above, here are some more pictures, and my theory on the failure mode.

The witness in the euro underseal is the first thing that drew my attention (left mount / missing bolt head) :

A closer look, note the vertical wear pattern from the bolt head :

On the picture above, also note the wear on the bush from the bolt shank (bottom edge, closest to the camera).

Here are some more photos of the bush wear from the shank of the bolt :

Now the Ford tech said that the remaining right hand bolt was really tight to remove, and he feared breaking that during the strip down.

This is the right hand thread in the diff cover, remembering that this thread has only had a bolt inserted and removed once, it clearly has a damaged / cross threaded thread form :

Which is really difficult to photo, but very apparent from the other side of the mount :

What I can’t capture on photo, is that the first 2/3rds of the thread, appear to run at a slightly different angle to the last 1/3rd.

Again not easy to capture on a photo, but the broken bolt looks offset in the bore, almost like it’s really being driven skewed into one side of the thread :

To me, these next two are the most telling photos …

Here is the mounting face on the ‘good’ side (even though we know this side still had a suspect thread), note the witness mark where it’s been clamped tight against the subframe bush :

Now compare that to the failed side, that has zero witness to being clamped, AND even has euro underseal overspray on the mating face, even though the underseal is applied after assembly :

It’s very obvious on this comparison :

So my unprofessional armchair conclusion :

• Neither right or left threads were good from the factory.
• The right thread allowed for some clamping force to the mating faces.
• The left thread provided no clamping force to the mating faces.
• No clamping force = all the stress through the shank of the bolt = bolt failure due to fatigue.

I’m open to, and interested in other opinions / theories, so please feel free to chime in with any alternatives

WD

Edit : to fix picture links.

WD

 

[Highvolts]

Yes, I found mine sooner than you, but a bit late for a better outcome ...

Expand the post to see the pics, or click my name in the quote to take you to the source)



WD

While mine is a 2022, I only have 8300 miles on it. I work from home and don't drive a whole lot. But it looks like what you had happen is what will happen to mine if I left it alone.

 

[WD Pro]

While mine is a 2022, I only have 8300 miles on it. I work from home and don't drive a whole lot. But it looks like what you had happen is what will happen to mine if I left it alone.

Or get regularly excited with the gas pedal - I broke mine at 2.5k ...

WD

 

[Highvolts]

That is a bummer. Because it is still under warranty I would take it back to the dealer. However, you can be sure that they are going to try and tighten the bolt and call it good.

I would try to work out with them that you can be present when they remove the bolt to determine if it is in fact cross threaded. If so, then they would need to tap the diff or , better yet, helicoil the diff to repair it. Most important is to not allow them to tighten it just enough to stop the washer from rattling. That would only kick the can down the road leaving it to be dealt with at a later date.

Yea. Fortunately, it's just into the rear diff cover, so worst case I can just replace that.
Going to dealer in a few weeks. We'll see.
Appreciate your input

 

[Highvolts]

Or get regularly excited with the gas pedal - I broke mine at 2.5k ...

WD

Well, I do have fun with the vehicle.

Kinda crazy this is out there.

 

[WD Pro]

Well, I do have fun with the vehicle.

Kinda crazy this is out there.

Apparently mine wasn't a 'one off' ...

Joking aside, I worked out a deal with the dealer and when the new cover went back in, some new bits and pieces also got fitted, at very preferential rates (as they were pretty much doing the work anyway).

Alignment sleeves / subframe bushes / upgraded diff bolts / diff bushes / H pipe - just a thought for you.

It's also an easier pill to swallow when they are tearing into a 'new' car - 'well its a bit crap its happened, but I was going to do these mods anyway, so now its better than it was before etc etc'.

Every cloud has a silver lining ... lol

WD

 

[Highvolts]

I

Apparently mine wasn't a 'one off' ...

Joking aside, I worked out a deal with the dealer and when the new cover went back in, some new bits and pieces also got fitted, at very preferential rates (as they were pretty much doing the work anyway).

Alignment sleeves / subframe bushes / upgraded diff bolts / diff bushes / H pipe - just a thought for you.

It's also an easier pill to swallow when they are tearing into a 'new' car - 'well its a bit crap its happened, but I was going to do these mods anyway, so now its better than it was before etc etc'.

Every cloud has a silver lining ... lol

WD

I have wanted to do some of those mods as suspension work is my favorite mod to my cars. Kinda glad I didn't yet cuz they would probably say I broke it.

Got an appointment at the dealer in a few weeks. We'll see what they say.

 

[WD Pro]

I have wanted to do some of those mods as suspension work is my favorite mod to my cars. Kinda glad I didn't yet cuz they would probably say I broke it.

This is all dejavu for me !

That was exactly my position, and my exact thoughts at the time.

I even had all the bits lined up in the garage and ready to go, but I was lazy and hadn't sorted it.

I crawled under the car one night to start getting my head around the H pipe, and then spotted the missing bolt head

My car was out of action for a long time when it happened - it's not a stock part over here, and then more delays with the part supply.

Local dealer was great throughout the process - I get on really well with the head tech that worked on the car. He kept me fully updated, left it up in the air on the ramp so it was safe, and even plugged a CTEK into it for me

WD

 

[Highvolts]

Update - Had an initial appointment with the dealer on October 2nd where they saw what I saw and also couldn't tighten the bolt. They were afraid of breaking the bolt so they ordered a replacement bolt and sent me on my way.

The new bolt came in and I took the car in today. They got it back up on the rack and supported the differential and gently removed it with an impact and a lil heat from those induction heaters. They inspected the threads on the rear differential cover and they appeared ok. There was a ton of lock tite on the original bolt and he thinks it got stuck in the threads and caused the bolt to not seat all the way. The very last thread on the bolt is a little mangled, but nothing crazy. I also see some tool marks or something on the threads.

The new bolt went in super easy and torqued right down. No issues.

The only sorta issue was that the bolt was not covered by warranty. If it had broken and caused issues with the differential, it would have been covered. If I would have tried to fix it and broken it, warranty probably would have been voided.

It only cost $115 for the bolt and repair. So I'll count that as a win. @WD Pro - Thought you might like to hear the update.

Here's the old bolt:

 

[WD Pro]

Great news (other than the nominal cost) !

A far less invasive repair than what mine needed (although I did use my situation to my advantage).

I do think they should have covered it though, why is ‘incorrect / incomplete assembly’ not covered under warranty ?

WD

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