Front locker questions

[Ralphramst]

While running the Rubicon a couple of weeks ago I ended up in 2 wheel drive about half way through. ( Buck Island). Front axles would turn but no torque to the ground. Tore it apart today. Stripped the splines on driver front on hub side of My RCV axle. Tore the passenger side apart and it looks good.
My question is why would my passenger tire not pull when the front locker engaged????
I am afraid I have some issues with the locker also but with all the fly by wire on the Bronco I was curious if someone had any ideas.
By the way we made it out in 2 wheel drive with the rear locker on when needed. Thank god I went with a warn winch. Needed it about a dozen times to get over some of the obstacles.
Running 17x12.50x37 swamper IROC tires. RCV axles, Metal Cloak skid plates and rock sliders.

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[Brian_B]

My question is why would my passenger tire not pull when the front locker engaged????

That's a good question. What you describe sure sounds like default axle action without a locker engaged.

If the driver's side stripped, maybe something up in the carrier is borked too?

The fly by wire crap would prevent you from engaging the locker at all - if it's letting you lock it, then it should lock - the locker mechanism itself is pretty basic

See pg 14 (listed as Pg 12)

https://media.spicerparts.com/cfs/f...token=eyJhdXRoVG9rZW4iOiIifQ==&store=original

 

[Alanp970]

Wait….BOTH front axles were turning but no drive to the tires? Sure sounds like your locker was still working and the problem is further outboard

 

[Bikeric]

My front locker only works sometimes. I can visually see when it’s not properly engaged when the lock is gray instead of yellow.

https://www.bronco6g.com/forum/thre...n-modified-rebuild-planned.59015/post-1940956

 

[RagnarKon]

Isn’t there an intermediate shaft on the Bronco on the passenger side?? Wonder if you blew out the splines on the intermediate shaft.

I agree with @Brian_B. Either the locker didn’t lock, something broke on the carrier, or there is an intermediate shaft you busted the spines on.

 

[Brian_B]

Wait….BOTH front axles were turning but no drive to the tires? Sure sounds like your locker was still working and the problem is further outboard

Isn’t there an intermediate shaft on the Bronco on the passenger side??

There is internal to the FDU - p/n 33

I imagine it would sound like a bag of hammers if it had blown and you have the front axle engaged - there would be metal all over the place in there

 

[Brian_B]

My front locker only works sometimes. I can visually see when it’s not properly engaged when the lock is gray instead of yellow.

https://www.bronco6g.com/forum/thre...n-modified-rebuild-planned.59015/post-1940956

Hmm this is interesting. As far as I know - there is no actual sensor or anything that tells when the locker is actually locked (the Jeep has one I think - I saw someplace their wiring harness has the extra wire for feedback but I’ve never actually owned or worked on one to know for certain)

I suspect the only way the Bronco would “know” would be that fly by wire crap is locking the Front locker out and preventing it from even trying for some reason - like speed over 20mph or something

 

[HoosierDaddy]

Fly by wire sounds cool, but call it what it is,
a computerized nanny.

This has been a complaint since the beginning, too much tech taking control at really bad times. It makes these rigs seem very fragile.

There have been a few different issues with the nanny deciding you really don't need the drive mode or option you selected.

Like when that trick "advanced" transfer case with the clutch gets hot while off roading and locks out the 4x4 as it sees fit.

.... or unlocking the lockers due to some unknown parameter that it doesn't like.


All of a sudden, the standard transfer case and Ford's aftermarket manual locker switches are really appealing.

 

[Ralphramst]

Pretty sure I broke the intermediate shaft on the passenger side and then stripped the splines after digging a little deeper. Thanks for all the help everyone!

 

[Brian_B]

I approve of wrenching in flip flops

also those CV shafts (assuming those are the RCVs) don't look too bad but maybe it's just the resolution on the photo. Also not seeing what those connect to so only seeing half the story.

 

[Wharthog]

Did you have the front locker on for a while? I remember reading somewhere that you are only supposed to have it on for when you need it and then turn it off. Not sure if this is the reason?

 

[Alanp970]

So for a little clarification, if it was the intermediate shaft that failed then both axles wouldn’t have been turning, correct? Only the side with the failed hub?

 

[Brian_B]

So for a little clarification, if it was the intermediate shaft that failed then both axles wouldn’t have been turning, correct? Only the side with the failed hub?

Really depends on how it failed.

If it stripped teeth on the spline clear off, or if the shaft sheared in two - then the passenger side shouldn't be able to spin at all.

But if it just rounded some teeth off - it may still spin under no load, but as soon as you try to deliver torque with it it just slips/grinds.

 

[Felix808]

those CV shafts (assuming those are the RCVs) don't look too bad but maybe it's just the resolution on the photo. Also not seeing what those connect to so only seeing half the story.

I agree, the axles don't look that bad

 

[RagnarKon]

So for a little clarification, if it was the intermediate shaft that failed then both axles wouldn’t have been turning, correct? Only the side with the failed hub?

The front differential is on the driver's side of the vehicle. The driver's front CV axle plugs more or less directly into the differential side gear. But the passenger side needs an intermediate shaft to close the gap between the CV axle on the passenger side and the side gear on the differential.

It sounds like @Ralphramst broke (or rounded off) the splines that connects the driver's CV axle to the wheel hub. That would have prevented power to the driver's front axle, but it explains nothing about the passenger side. But he also stripped the spines on the intermediate shaft, which explains why the passenger side wasn't spinning either.

Either way... when you strip splines like that, it typically will spin just fine as long as the wheels are off the ground—there still is enough friction left to spin the tires. But once you put the wheels on the ground and put some actual load through the CVs it would have started skipping splines, and no torque would have been delivered.

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