ZFG: I guess I'm a fanboy now too

I guess if it was done with a HP tuners device and in the format that is needed you might be ok. I'm pretty sure the file my LMS tune saved won't be what they need. So I'd rather play it safe than be sorry down the road.

Yeah it was originally done with the rtd an hp tuners. Same format

Why not just buy the bolt and add it yourself? Im sure you can buy the bolt alone from diagrams. As much as I love this Explorer, theres a lot to dislike about it too. Feels unfinished in a ton of areas.

I wonder if this was one of those cheap cost saving things Ford did to the 2021 models that were standard on the 2020 models. My 2020 Platinum also has 2 bolts

My 21 also only has one bolt...

You would have to cut out the hole in the frame crossmember, weld a sleeve in for the bushing, press the bushing in, then put the bolt in. Not as simple as just throwing a bolt in the hole.

My guess is it was a running change(for what purpose I dont know) and they dont want to make a new stamping die for the frame crossmember. If that wasnt there, nobody would be the wiser. The small hole thats in that section is likely a jig hole for the drilling robot to make its cut. Kinda like all our vehicles still have the removable piece on the front bumper for the tow hook, yet that was really an early 2020 feature only... but they wont make new front bumper covers to delete that, im sure the cost is quite high to do that and not worth it.

Wow! I thought it was a simple bolt screw in as some said there were threads already in the hole. That blows tho, wonder if it will be a more common thing as more and more people will start towing.

This is precisely the barrier to entry for why i didnt go that route. I ordered a 2nd bolt thru Fordpass but it never arrvied. Had it arrived, i would be left wondering whether adding the 2nd bolt w/out any rubber bushing to allow flex would actually help or hurt the situation. I'm sure if i added the bolt without the bushing, and then broke the OEM bolt, Ford would point to user error/etc for making the rig too stiff and try to avoid warranty coverage...

My 2020 has two bolts also.

No the DIFF is threaded already, not the hole in the frame. The "hole" needs a lot of work to get a bushing into it then bolt it up. Not something for the faint of heart. Do-able, yes... easy...no... A competent fab shop could likely knock it out in a few hours depending on what all needed to be taken apart. Im GUESSING the diff needs to come out to get clearance. Likely a bunch of other stuff to(rear swaybar probably, just spitballing here).

Does it give any benefit? MAYBE.

Im guessing the bolt/bolts are at LEAST 10.9 and MAYBE 12.9. If its 10.9(grade 8 equivalent) and im spitballing on diameter since I dont know it, its likely got a shear strength somewhere in the 25000lb area. If its 12.9 its likely closer to 30000lbs... Thats a LOT OF FORCE. So high strength steel bolt into aluminum diff... Im actually surprised it didnt crack the diff since aluminum is FAR weaker than steel.

I think the OP's situation is a fluke IMO(not to put him down or anything remotely like that, his experience is his experience)... The first time it broke(along with a few other parts) they were putting some crazy forces on it(reverse emergency braking with a boat attached with no trailer brakes). That situation was possibly never engineered to occur nor tested for. The second, who knows if the bolt was bad, install was bad(over torqued), etc...

The OP's situation is the ONLY one of these I have read about and had it not been for this thread and his other one(about his driveshaft) I dont think anybody would be talking about this. Are there other reports out about it? Im not on Facebook so maybe on there there are... I would be interested to know if this is more widespread than 1 vehicle...

Im far more concerned that my entire front end sounds like all the joints are loose vs. only having a single bolt in the rear diff vs. 2...

Posted for quick visual comparison.

Clearly, this change was intentional. Even the bushing in the single is different.

I previously thought a 2021 would be getting all the kinks out of 2020s but it turns out there's a heck of a lot of cost cutting that was done.

So the bushing design changed...

I need to see if I have that bushing on mine with the large metal center.

That likely is what allows them to go to a single bolt vs. the 2. That design likely has a lot less flex/deflection than the original 2 bushings and the second bushing then was not needed. The older bushings look like when they are installed they get twisted/distorted from the get go likely causing issues. likely not optimal and not as designed, so the engineers likely went back to re-design things and also figured out that with the new design, 2 werent needed.

Maybe we should start a dedicated thread to this instead of continuing to clutter up the OP's ZFG thread...

Yeah, good point about possibly a single bolt getting the old bushings and failing. I still think a single is not as good because it's not centered relative to the differential. The differential was probably designed to be mounted with the two bushings but they decided to save $50 and go single.

@STFan Could you move the posts about the rear diff bushings over to @Cdubya original post about this issue, please?

That also strikes me as an odd change. What was the original reason to move to a single bushing? Assuming this was done due to some valid, yet obscure reason, could it be that @Cdubya 's experience- despite the Ford Tech's assumption- be related to another drive train issue that might have been overlooked? I noted in the original thread the existence of TSBs for driveshaft balance problems. This could have caused harmonics in the drive line that eventually eroded the diff mounting. The fact that it was fixed and the problem repeated, combined with no other reports of this type of problem makes me wonder if the problem is not related to the bushing, but exists elsewhere.

please see posts #44 and #46 of this thread. i agree, info should be moved.

I made one in the troubleshooting section a while back. https://www.explorerst.org/threads/beware-driveshaft-kaboom-from-emergency-auto-brake.2148/

Yeah, different design altogether. Knowing Ford tho, pretty sure there was next to no testing on the newer design to see how it holds up.
As rjacobs said, could probably not be a huge deal, just interesting change tho.

interesting that the bushings on the two bolts are different and oriented differently also.

blaster9 says another owner on FB with one bolt had the same issue. 2 cases to me is enough to be a potential problem.

Thats your other thread I was referencing. So between that one and this one, I have read not a single other thread on this bolt breaking.

I dont think the rear diff in the ST is exclusive to the ST. The gear ratio is, but I dont think the physical diff housing or frame crossmember is.

So how many explorers were built in 2021? There were ~225k made in 2020, guessing 2021 will be less than that due to production constraints.

So lets assume there will be like 10% less, lets say 25k less, so 200k vehicles built in 2021... And this is basically the ONLY report I have seen of this bolt breaking(there may be others, but as I said earlier, I am not on Facebook which may have more user presence). I searched through ExplorerForum also and didnt see a single thread referencing this bolt(it seems those guys HATE the 10spd trans while most of us over here dont have major issues with it).

Again, not trying to diminish Blaster9's issue and experience, but I am also not trying to get wrapped around the axle over it either or go rushing to my Ford dealer and demand a second bushing and bolt be installed.

Because all of us are tuned by ZFG and he fixed it… lol

LOL I havent gotten my tune yet..... but I have no big complaints on the 10 speed. Seems like the majority of them have the 4 cyl so could be an issue with the powerband?