BS or not?

Assocracer said:

Ok, so I switched my 2011 Ranger Sport 4x4 into four wheel drive a few weeks ago and the front end started whining like a little bitch. So I switched it off and it took about 3-4 min for it to finally disengage the 4x4. When it did it made a huge thud and shook the whole truck. Tried it again with the same results. Later that day I did it one more time to show the wife what I was talking about and then it wouldn't come out of 4x4 at all. When I got to where I was going, I backed up about 10 feet and the 4x4 disengaged without a sound or so much as a small shudder. Took it into the dealer, they tell me the transfer case is shot. Ok, thank God for extended warranties. They put a new transfer case in. I pick it up last night and try the 4x4 as I'm pulling out of the dealership, and it's doing exactly what it did when I brought it in. Turned around and took it right back. I just get a call telling me that the problem is because my front tires have 6/32 tread (which I didn't think they were that low) and that the rears have 11/32 (replaced them a couple months ago). Now I sold, mounted, and balanced tires for 10 years. I know that when you replace tires on a 4x4 you should do all 4, but when I replaced the rears, the fronts were still somewhat new (had about 15k on them). The dealer replaced those when I bought the truck and left the old ones on the front. Those are the ones I replaced. I've never heard of tires causing this kind of problem before. Can someone school me on this or tell me I'm right and that the dealer is full of shit?

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pjtoledo said:

that part has me a bit confused. did you use 4 wheel drive on dry pavement?

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adsm08 said:

Ok, so the transfer case is not a center differential, which is what full time AWD vehicles have. Even if the tires are all perfectly the same size when you turn you usually have 4 tires moving at 4 different speeds. In 4x4, even with a diff at each end of the vehicle, this causes a condition we call "drive line windup", which is exactly what it sounds like. The system gets placed under stress and tension by the different linked wheels trying to move at different speeds with nothing to give them any slip. This is why a 4x4 vehicle, in 4x4, will hop through a turn on dry pavement. The tires are giving that slip.

If you have tires that are mismatched in size, even just a bit, and put it in 4x4 on dry pavement this will happen, even going in a straight line. The worse the mismatch the worse the windup. The tires tend not to hop going in a straight line though. So then what happens is you stress the internals of the transfer case, putting them under tension, and start trying to wind up the driveshafts like the rubber band attached to the propeller on one of those balsa wood airplanes. It goes "Bang" when you shift it back to 2WD because you suddenly take that tension off as the front drive disengages.

Or sometimes the shift motor isn't strong enough to pull it back out, and then it gets stuck. But backing up will relieve that tension, and let it come out without a bang.


So yes, under the conditions you described your experience, the banging, the noises, the trashed transfer case, are all 100% normal, expected things to have happen. You did that to it by abusing it in a manner that, if you had bothered to read the owner's manual, you would have seen is an exact condition you were instructed to avoid being in, namely in 4x4 on dry pavement.


The dealership is right, and honestly the warranty shouldn't have been honored at all, because I don't know of any warranty, extended or otherwise, that covers abuse, which is what this is.


If you feel the need to exercise your transfer case keep these few things in mind.

1) Never move in 4x4 on a hard dry surface. Even gravel doesn't always have enough give for it to be safe. Ford says ice, deep snow, or mud are the only acceptable safe terrains.

2) All your front drive line components, including all the transfer case internals, are moving all the time because of the live-axle setup in the front. These pieces are not sitting static and "flat spotting" if that is what you are worried about.

3) The only piece of your 4x4 system that will benefit from being "exercised" is the shift motor. You can do this by just shifting in and out a few times while stopped without doing damage.

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bobbywalter said:

rare moments.


hmm. I have to 1000 percent disagree with your assessment of this situation even remotely entering the realm of abuse..


not even in the same galaxy.

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adsm08 said:

That's because we live in galaxies where "abuse" has different definitions.

My threshold for abuse is when Ford says "don't do that".

I am quite sure yours is much higher.

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adsm08 said:

Ok, so the transfer case is not a center differential, which is what full time AWD vehicles have. Even if the tires are all perfectly the same size when you turn you usually have 4 tires moving at 4 different speeds. In 4x4, even with a diff at each end of the vehicle, this causes a condition we call "drive line windup", which is exactly what it sounds like. The system gets placed under stress and tension by the different linked wheels trying to move at different speeds with nothing to give them any slip. This is why a 4x4 vehicle, in 4x4, will hop through a turn on dry pavement. The tires are giving that slip.

If you have tires that are mismatched in size, even just a bit, and put it in 4x4 on dry pavement this will happen, even going in a straight line. The worse the mismatch the worse the windup. The tires tend not to hop going in a straight line though. So then what happens is you stress the internals of the transfer case, putting them under tension, and start trying to wind up the driveshafts like the rubber band attached to the propeller on one of those balsa wood airplanes. It goes "Bang" when you shift it back to 2WD because you suddenly take that tension off as the front drive disengages.

Or sometimes the shift motor isn't strong enough to pull it back out, and then it gets stuck. But backing up will relieve that tension, and let it come out without a bang.


So yes, under the conditions you described your experience, the banging, the noises, the trashed transfer case, are all 100% normal, expected things to have happen. You did that to it by abusing it in a manner that, if you had bothered to read the owner's manual, you would have seen is an exact condition you were instructed to avoid being in, namely in 4x4 on dry pavement.


The dealership is right, and honestly the warranty shouldn't have been honored at all, because I don't know of any warranty, extended or otherwise, that covers abuse, which is what this is.


If you feel the need to exercise your transfer case keep these few things in mind.

1) Never move in 4x4 on a hard dry surface. Even gravel doesn't always have enough give for it to be safe. Ford says ice, deep snow, or mud are the only acceptable safe terrains.

2) All your front drive line components, including all the transfer case internals, are moving all the time because of the live-axle setup in the front. These pieces are not sitting static and "flat spotting" if that is what you are worried about.

3) The only piece of your 4x4 system that will benefit from being "exercised" is the shift motor. You can do this by just shifting in and out a few times while stopped without doing damage.

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adsm08 said:

That's because we live in galaxies where "abuse" has different definitions.

My threshold for abuse is when Ford says "don't do that".

I am quite sure yours is much higher.

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ericbphoto said:

Agreed. If you ran 4wd in hard, dry pavement, you abused the system. If you don't like the term "abused" then we can say "improperly used" or something like that. But it means the same thing. The system was used in conditions that it was not designed for and, therefore, breakage occurred.

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