Tremor front diff explodes at 7400 km

[EcoBeastCA]

I guess I didn’t think so because of the bed etc, it’s likely to get dinged up with towing or using bed. I don’t think I’d ever lease, I’d rather have no limitations on mileage or modifications. Yes I pay more per month on my loan but after 4 years my payment is $0. Different strokes for different folks I guess. Learn something new every day.

I like that leasing gives you an easy exit strategy in case you got a lemon. And I've been unlucky enough over the last 10 years or so to know that happens a lot more often than it should. Case in point...

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[powerboatr]

WHOLLY cheese dip

i dont want to ping on OP
but this was 4H and rocking? how severe or fast was said rocking? wheels still rolling in one direction then shift to reverse? i would have them also look at TCASE and transmission case and or mounts
i have not tested the fast shift of the ten speed, nor shall i.
just seems weird imo that we have a few splitting in half

i pull stuff all the time in 4L as it allows me idle in or out of spots with the trailer on river rocks

would be nice to access that broken case and do some tests on the material, etc.

 

[SALEEN961]

What really concerns me is that this happens in 4H where stresses are NOT at their max. Using my STX as an example with a Low range on the T-Case of 2.72:1, and the 10R80’s 4.69:1 1st gear ratio, and a 3.31:1 final drive; in 4L that means my final drive ratio is like 42:1. Multiply the 5.0L’s 410 lb ft of torque through all that or step up to the 3.5L’s 500 lb ft and that’s some serious twist this diff needs to hold. It’s concerning to see failures in 4H instead of 4L to be honest.

A lot of people forget about torque multiplication in an ICE vehicle. This is why in that silly tug of war that EV channel did they were shocked the 5.0 F-150 was able to tug on par with the Lightning Platinum. In Low Range a 5.0L is actually getting more torque to the ground than the Lightning EV is capable of at its best. Then the 5.0 broke traction and was finally pulled spinning its wheels since it was 1,000 lbs + lighter (it was inevitable, weight wins). Low Range puts serious torque down through multiplication like leverage on a handle, and stresses are high. This hunk of aluminum seems underwhelming for the task.

Torque multiplication is definitely something that can't be overlooked. On my 2021 3.5EB, the minimum gear allowed in 4L is 2nd. With 500 lb-ft of engine torque, 2nd gear in 4L is 3940.2 lb-ft at the driveshaft. In 4H where 1st gear is allowed, that same 500 lb-ft of engine torque becomes 2348 lb-ft at the driveshaft.

If I were to modify the factory tune to allow 1st gear in 4L, my 620 lb-ft of engine torque would become 7686.4 lb-ft at the driveshaft. That kind of torque can break a lot of things very quickly.

 

[22Platinum]

If I were to modify the factory tune to allow 1st gear in 4L, my 620 lb-ft of engine torque

Livernois is claiming 671 ft/lbs at 18% driveline loss

 

[HammaMan]

Gas porosity is formed because molten metal is excellent at trapping gasses so as it cools these bubbles form

then your diff goes BANG

although i'm blown away at how perfect that failure is on the cross section

Every pic we've seen of blown front pumpkins has failed in the same spot (kinda given due to the nature the pinion pushes away the ring). Curious if any TOD trucks have failed or if the clutch isn't capable of holding full torque. I've been suspecting that it can't hold but 350ftlbs or so, basically the amount of power it was originally designed for.

 

[tony72cutlass's']

Every pic we've seen of blown front pumpkins has failed in the same spot (kinda given due to the nature the pinion pushes away the ring). Curious if any TOD trucks have failed or if the clutch isn't capable of holding full torque. I've been suspecting that it can't hold but 350ftlbs or so, basically the amount of power it was originally designed for.

interesting stuff, I just did a quick google on the brake away torque of this kind of clutch but could not find anything definitive.

 

[HammaMan]

Yo, WTH. Seriously @Ford Motor Company --- look at those casting imperfections. These front pumpkins are ticking timebombs.

 

[HammaMan]

Just to clarify what's going on here, the differential is the parts inside of the pumpkin. The pumpkin is popping. I suspect this ineffective / deficient part is why the raptor R's torsen has been removed hoping that a wheel loses traction before the pumpkin explodes. The pinion gear is producing enough force to shove away the ring gear and pop goes the housing. This isn't a diff failure.

Notice the angles on the gears, in reverse, the pinion and ring gear's helix cut ramps literally force the pumpkin apart like driving a wedge into it.

 

[fordtruckman2003]

One of the prior threads on this.

Does it look like the crack is in roughly same area? Pics are a few posts down.

https://www.f150gen14.com/forum/threads/cracked-front-diff-housing.8435/

 

[SALEEN961]

Livernois is claiming 671 ft/lbs at 18% driveline loss

I'm actively trying to avoid a big torque spike around 2500-3500RPM so my peak torque will be a bit lower than theirs. My concern is increasing peak cylinder pressures too much in an RPM range that doesn't really help to make my truck faster. After 1st gear, I'm out of that RPM range anytime I go WOT. I just don't like the risk/reward profile of pushing for more and more torque in that RPM range.

 

[HammaMan]

One of the prior threads on this.

Does it look like the crack is in roughly same area? Pics are a few posts down.

https://www.f150gen14.com/forum/threads/cracked-front-diff-housing.8435/

That's a different failure mode right there (though quite a few piled on). What's interesting is that look at the marks on the pumpkin, there appears to be a mold defect, then what looks to be a QC marker next to it okaying it. Man these castings are ugly

Here's another....

And another pinion pumpkin buster

 

[powerboatr]

That's a different failure mode right there (though quite a few piled on). What's interesting is that look at the marks on the pumpkin, there appears to be a mold defect, then what looks to be a QC marker next to it okaying it. Man these castings are ugly

Here's another....

And another pinion pumpkin buster

that makes me hurt ...looking at that

some of odd casting marks can be from COLD molds, not meaning COLD as COLD
but not right temp when alum is poured in

either way...
its freaky the alum housing has been used for long long time and why are we seeing the last 3 years of failures early in life so to speak?

 

[HammaMan]

that makes me hurt ...looking at that

some of odd casting marks can be from COLD molds, not meaning COLD as COLD
but not right temp when alum is poured in

either way...
its freaky the alum housing has been used for long long time and why are we seeing the last 3 years of failures early in life so to speak?

It's magnesium. Given modern tech and all that entails, we shouldn't be seeing molds this ugly or a failure rate like this especially on non-abuse scenarios. Rocking back and forth in 4H? It's one thing if you're going nuts in the mud being a jackass, but common 4wd usage scenarios? Driving in the snow?

C'mon man

 

[powerboatr]

It's magnesium. Given modern tech and all that entails, we shouldn't be seeing molds this ugly or a failure rate like this especially on non-abuse scenarios. Rocking back and forth in 4H? It's one thing if you're going nuts in the mud being a jackass, but common 4wd usage scenarios? Driving in the snow?

C'mon man

magnesium? i thought it was alum?
oh well
but yes "normal" it should not give up

 

[Kanuck]

Just wondering if anyone knows. These trucks that have the front diff blow apart, are they from just one or both plants or a range of manufacturing dates?

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