4WD Failure

[austinVR]

What I found out with the FAD was that it wouldn't throw a code until you got into a condition where it expected all 4 wheels to be turning, but the front's weren't.

So if you were just tooling down the road with decent traction in 4H/4L, and the fronts were rolling along, the Bronco (and I) thinks everything is just ok. It wasn't until the rear wheels lost traction and you were hoping the fronts would pull you out that it would throw a code (and I would start throwing things).

Now, I'm not sure if the Tcase has a feedback signal that checks engagement, or even if it does if the failure mode couldn't work around that anyway in the case of what may be the cause of this.

This is exactly what I am experiencing. You think it is all working because the dash and GOAT switch both indicate that the drivetrain is in either 4H or 4L. Until you're stuck and the front wheels are just sitting idle. Then when the vehicle realizes there is no front wheel speed while the rears are turning it disables the 4x4... which obviously wasn't working in the first place.

Not sure how I could test the 4A. I tried to a bit this morning on some dirt roads but the tires still had too much grip to tell me anything definitive.

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[crenca]

Not sure how I could test the 4A. I tried to a bit this morning on some dirt roads but the tires still had too much grip to tell me anything definitive.

Perhaps too subtle, put it 4A (& sport mode if you have it), take a 15mph turn and get deep into the throttle as you straight end out. The torque steer, traction, and directional stability compared to 2H is apparent.

 

[Brian_B]

I was able to test 4H by spinning out in gravel/sand, but had too much grip on dirt. Snow it had to be deep or the tires would dig and catch before they would throw a code

Could also test by jacking the front end up and spinning tires by hand - very obvious then if it isnt locking in - but that doesnt work with 4A

 

[austinVR]

Well... I returned the Bronco to shop after speaking with the service manager who said he'd get a more experienced technician assigned to it. They ended up finding the front differential broken. I am quite shocked by this because I baby this thing and drive in 2H; very rarely use 4x4 - only briefly in sand or snow/ice a few times a year. Have had no typical differential warning signs like binding or noise. HOWEVER.... the diff had been leaking and the pinion seal was replaced under warranty during my initial visit a couple weeks ago. They conveniently don't remember how low the fluid level may have been at that time.

Request is out to Ford right now to see if the diff will be covered. Unfortunately, I just lifted and installed 37s last month (approx. 300 miles ago) which could potentially be cause to deny warranty claim. So we'll see what they say...

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