Beware: Trail Turn Assist causes axle weld failure that dealer won't warranty!!!

[RedHotLava]

My 23 Badlands Sas was built 4/13 and has been on plant hold ever since(over 50 days) I just found out from customer service supervisor it is because of the rear axel. She couldn't give me any further info other than, during inspection it was put on hold for the rear axel. I am thinking they may be addressing the plug weld issue and holding current Bad Squatches or mine was just bad..

At least they told you the truth. They told us ours shipped but for SOME odd reason, the shipping just keeps getting bumped every week for 2 months now....WEIRRRRD......

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[MJ12]

The first guy I talked to today tried to feed me some line saying it was built 4/13 and is just waiting to be updated which I knew was BS, from already finding out it was on plant hold since 4/13 according to a different agent I spoke to last month, (they didn't know why). I asked to speak to a supervisor about my grievances with the lack of transparent communication on a 60k+ vehicle I ordered in 2020. The supervisor named Cayla called me a couple hours later and seemed genuinely helpful. She stated she can see the various stages of QA checks from 4/13 that it had passed and that it has a code indicating the rear axel was flagged during the QA checks causing it to go on plant hold. She could see that 2 days ago an update was added and is showing "pending" and gave me her e mail to contact her later this week when that update may go out of pending status and she can see what that update was. I really didn't expect to get any info, even if it was all lies (I don't think so...) it was still at least an attempt from Ford rather than the last 2 times I have called and get told very little other than its in production and on plant hold, despite the "built" e mail I got on 4/13. Good luck to all those still waiting.

 

[87-Z28]

Just started reading some of the details for this thread.

Concerning rear axle housing plug weld capacity.

it is slightly disappointing to only have 3 plug welds. They can only carry about 60% of the axle housing capacity.
@RHeinz @flip @Bmadda @Snacktime

the result is broken tube welds. if the axles were smaller they would snap instead.

on a 1g bronco, I once sheard the axle off one side because one rear brake was working and the other side broke under heavy braking.

THIS… Regardless of how torque gets into housing. Are welds sufficient??? This can be calculated reasonably well. approaching this from plug weld design point of view. Are plug welds sufficient to carry torque from axle shaft housing?

max torque housing can carry is close to 90,000 in-lbs. T= YS * J / r. Axle housing diameter looks to be 2.5” with 3/8” wall. Then polar moment of inertia J is then about 2.3. For a yield strength of mild steel at 50 ksi.

plug welds diameter is close to 5/8” so each plug welds can carry a torque of 20,000 in-lbs. assuming evenly distributed stress and weld can develop 50 ksi YS similar to axle housing. T= r * A * YS. Moment arm r is housing radius (1.25”). Area of plug weld is 0.3.

so 3 plug welds can carry (60/90) about 66% of the max torsion capacity for the housing.

Apparently Jeep has 4 similar sized plug welds. If axle housing is identical, then that design allows for 90% of total torsional capacity.

Are bronco welds under designed? Possibly. not sure why go down to 3 same size welds? Time and cost likely? No matter how torsion gets into housing, surely 60,000 in-lbs (5,000 ft-lbs) is plenty for TTA. Bad welds is another story.

Current Jeep D44 welds. There are 4.

 

[TheGriffin1313]

Could the 4 door be more susceptible to this failure do to the torsion generated based on the wheelbase length?

 

[7sKnuckledragger]

Everyone wants to run 37”+ tires and hit trails but nobody wants to spend the money to actually run bigger than 35’s.
know your running gear and that’s where the money goes. Pull your housing, weld it, truss it, box in your shock mounts etc. or put in a free float 60. You wanna run big tires but get mad at foes when things break. If you wanna crawl the mall stock gear is fine. Folks will dump 5k into coil overs to wear a hoodie that says “KING” but won’t build a housing or drive line that will take a mild trail.
nothing personal just my 2 cents as someone that’s been building and breaking vehicles on trails for a long time.
Good luck fellas
-cheers

 

[87-Z28]

Everyone wants to run 37”+ tires and hit trails but nobody wants to spend the money to actually run bigger than 35’s.
know your running gear and that’s where the money goes. Pull your housing, weld it, truss it, box in your shock mounts etc. or put in a free float 60. You wanna run big tires but get mad at foes when things break. If you wanna crawl the mall stock gear is fine. Folks will dump 5k into coil overs to wear a hoodie that says “KING” but won’t build a housing or drive line that will take a mild trail.
nothing personal just my 2 cents as someone that’s been building and breaking vehicles on trails for a long time.
Good luck fellas
-cheers

Agreed. Of course.

every design has it’s limitations. Anything can be redesigned and modified. Some of us are just trying to more accurately determine the limit states for the stock design envelope.

 

[omi205]

Someone in the beginning comments nailed this. When I demoed the Bronco at the 2021 Los Angeles auto show. They did the trail turn assist…on a large patch of sand (atleast 6 inches in depth from the pavement and about 70x70ft) that they created in the middle of a parking lot on the side of the convention center. Meaning they were demoing TTA about 300 times a day for 5 or so days straight. Thats just at the LA auto show that I attended. Now times that by all the different city auto shows. And toss in the Bronco rodeo demos.

Long story short, If this was a problem. A genuine problem. Ford would have caught this by now. There vehicles would have been rendered “broken” after one day of use/demoing at any auto show. But that didnt/is not happening.

So my real question is what are people doing with their bronco (please be honest) that lead to this happening?

This reminds me of the guy that posted about rust under his seats and head rests and and was upset that Ford wouldnt give him a new bronco under warranty. Told everyone “my bronco has never been wet or near anything that could cause this”. And several days later after all the comments on the post claimed “that’s impossible, what did you really do”…the truth finally came out. Which was “the bronco had the top off all summer at the beach house right on the ocean.” Smh.

Im not saying OP is lieing but I am saying something dosnt seem right.

 

[dgorsett]

I'm of the school that it's not TTA but twisting of the housing when the rear is at max articulation. The control arm under compression twists the axle rearward, the side with doop pulls forward. Add to this, lift, non compessable aftermarket bushings and inadequate welds and you have an issue.

 

[Hossfire]

The larger diameter tire will have more “resistance to slipping”, requiring more torque to get it to slip, thus transferring more bending moment into the entire differential system.

The bending moment (torque) in the axle (and the equal and opposite force in the axle tube), is the tangential force (traction/friction) at the surface of the tire times the radius of the tire….. M=F*R The moment (torque) is measured in ft.lbs. Just like a torque wrench.

I agree. It's basic physics. The larger tires create a greater coefficient of friction to overcome. You apply more power, stress the axle and...things happen.​

 

[BigMeatsBronco]

I'm of the school that it's not TTA but twisting of the housing when the rear is at max articulation. The control arm under compression twists the axle rearward, the side with doop pulls forward. Add to this, lift, non compessable aftermarket bushings and inadequate welds and you have an issue.

this definitely has a twisting effect as well.
problem is more dramatic because the upper control links are so short, and not traveling in the same arc as the lower longer link.

 

[Owl]

So go to a different dealer. Its not like you're married to the dealer you bought your Bronco from.

 

[broncosaurus_bend]

Just sharing as a PSA…I do not use TTA but started leaking from the plug weld on the rear passenger axle. Not a ton, but noticeable. Due to “scrapes and marks on the diff and undercarriage indicating excessive impact from rocks it is not covered as a factory defect”. I don’t know why Target has to make their speed bumps so high…but word to the wise, check your axle plug welds, get a diff skid and paint it before you go in for warranty work.

 

[gammaguybronco]

I've been watching this thread for awhile. I'd like to upgrade my SAS Badlands from 35" to 37" tires sooner than later. Due to these weld failures I've been holding off since I do use TTA when screwing around in the Outer Banks. I've never actually run into a situation here in NC where I've needed TTA to get me out of a bind. Is this issue so worrisome that I shouldn't upgrade my suspension and put 37" tires on my Bronco or is this overblown?

 

[Noremac]

I've been watching this thread for awhile. I'd like to upgrade my SAS Badlands from 35" to 37" tires sooner than later. Due to these weld failures I've been holding off since I do use TTA when screwing around in the Outer Banks. I've never actually run into a situation here in NC where I've needed TTA to get me out of a bind. Is this issue so worrisome that I shouldn't upgrade my suspension and put 37" tires on my Bronco or is this overblown?

I have never found a need for using the TTA... I kind of laughed when this thread popped up in the unread though. I literally ran to town this morning, pulled in the back side of my land on the way back, and clicked it to say i have used it once.

It definitely causes a tighter turn, but still dont see the use in the trails we run.

My badlands sasquatch is on 37's and have zero suspension or steering issues... Also have had the drivers front tire 4ft in the air

 

[Valhalla]

I snapped a front left axle while using this on waldens ridge. I didn't have to use it but my buddy's wanted to see it instead of a four point turn like everyone else was doing. It did give me a better line. I have no rear axle weld issues as of this date. Waldens Ridge at windrock is extremely challenging. Look it up on YouTube. If you do less than that I'd say your fine. I run 37's on a body lifted rig.BTW the axle was replaced under warranty. I told them I was off road and had used the turn brake.

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