I have a "99" Chevy Silverado. The problem is the four wheel drive is locked in place. I have the auto 4 wheel drive push button on my truck. The 4 wheel drive is not engaged, but it is locked and the drive shaft spins even though I have it set on 2 Hi. What could it be?
Could be a lot of things but the button or the control module would be my first guess because two things need to lock for 4wd. The front axle disconnect and the Tcase. The fact that neither is doing so points to these items. (if front disconnect or Tcase engage you would not be able to spin front drive shaft.)
----------------- TheSnoMan.com
I'm missing something. Are you saying you can or can't turn the drive shaft if you get under the truck and try? With the truck stopped of course:)
Al
Sno,
How did you determine it's not in 4 wheel drive or the axle is not disengaged from what he wrote? I can't. He said "it is locked and the drive shaft spins even though I have it set on 2 Hi." He may be saying the drive shaft turns when he's driving it??
Al
Maybe but still the same in that either the tcase in that failing to disengage or the axle disconnect failing to decouple would cause drive shaft to turn with vehicle motion. If you jaceup one front tire and it turns with drive shaft then front axle is not decoupling. If drive shaft does not turn then tcase is not disengaging.
You know "Al" you could focus more on helping and less on a being a twit.
----------------- TheSnoMan.com
No doubt about that at all...
----------------- TheSnoMan.com
Look who is calling whom a twit. People that live in glass houses should not run around naked.
Al
Here is what you said:
"Could be a lot of things but the button or the control module would be my first guess because two things need to lock for 4wd. The front axle disconnect and the Tcase. The fact that neither is doing so points to these items. (if front disconnect or Tcase engage you would not be able to spin front drive shaft.)"
Sno,
Where did he say he could spin the drive shaft? Just copy and paste it.
Al the twit, but not the Snojob
I have a 99 Z-71 LT with pushbutton electronic transfer case. Mine is most definately stuck in 4WD. I have mashed freaking buttons for hours, but still stuck. When I could still get it to come out it would put itself back in everytime I caranked it automatically. If I would have thought of it, I should have took out a fuse or something then to keep it out. But now it is stuck, is there any way of getting this blessed thing out of 4wd other than manually dropping the transfer case and dismanteling it? Your help would be very much appreciated as I am on the brink of blowing it to kingdom come.
Unless they happen to be good looking females, then it's OK!
Al Bottoms Up Divers
Replace the push button switch (about $50 if you DIY), if that's not your problem now it will in the near future.
Al
We need more information. You do realize that it's "normal" for the front driveshaft to turn even in 2hi. This is an automatic t/case and the clutch pack that engages the front driveshaft is designed to put 5% torque towards the front driveshaft even in 2hi. In fact, if you crawl under the vehicle and attempt to turn the front driveshaft while it's in 2hi (this is assuming the front axle is disconnected, which it should be in 2hi) you should be unsuccessful. This is the way it's designed.
So what we need to know is: are you just worried because you see the front driveshaft turning even in 2hi, or is it actually locked in 4x4 while showing that it's in 2hi. If it's the former....you don't need to worry about it. If it's the latter...then we can move on to the diagnosis.
Ian
Here is the problem, Snojob! As far as I can tell, "Big Al" is actually interested in finding out what the actual problem is and then intelligently try to help the original poster. What you do is simply throw out whatever advice you think might be relevent "even" if you don't have a clue how the system works.
Look at your one statement in your paragraph above. "If driveshaft does not turn, then t/case is not disengaging". This is totally false, shows that you do not (yet) understand how the modern NVG 246 t/case works, and leads some poor sap looking for "correct" information on a wild goose chase.
Sometimes I think that you simply want to see how many threads that you can respond to, whether or not you give useful information appears to be totally irrelevent to you. I hate this type of poster. You think you are being helpful, but you aren't. And then you end up with a crowd of hanger-on's that believe much of what you say is true, when it isn't.
Ian
Hey, come on you guys-- please quit the flaming. I've gotten much info from this group, some good, some not so. We all do the best we can, and we take any info that may help us. Calling names only causes negative vibes. Quoting that man in LA a few years ago who was beaten by the cops, "Can't we all just get along?"
brody
Ian,
If it's in 4 wheel drive will it "crab" if you turn the wheels on pavement or is the t-case like the old Jeep Eagle? I'm assuming the front axle never disengages if the t-case supplies power in 2 Hi. Or does it?
I admit I'm not up on this system. How close is it to what's in a Hummer? And if you would, how does a Hummer lock the rear differential?
Al
No, because when the t/case is in 2hi, the clutch pack is applying approx 5% torque to the front driveshaft, but the front axle is disengaged. So you will not feel the crowhopping. Actually, you won't feel the crowhopping even if the front axle is engaged, because that is exactly what happens when you select Auto4hi. Now the front diff engaged, but the clutch pack is not engaged "enough" so that it slips and allows different shaft speeds...front to rear. As soon as the t/case module "see's" shaft speeds that are too far apart, it begins to apply the clutch to bring the speeds back together. The tcase has 3 speed sensors, two on the rear shaft, one on the front shaft. A scan tool is very useful for diagnosis as you can see whether the t/case is slipping or not.
When you enter 4hi, the clutch pack is completely engaged and the t/case behaves like an old style t/case.
I'm not up on the Hummer either, so I can't comment. The full size Hummer is a different beast all together....the fake one is nothing more then a GM truck with square body on it. That one probably has the exact same t/case. Rear end locking, not up on that on a Hummer.
Ian
Why don't you buzz off!
Ian
Ole Snowidiot was posting in the Dodge truck group for awhile with the same kind of crap. Half right info and bs the other half. He got ran out of there after about a month. You guys can have him...
Denny
Denny is correct. The info he was handing out at aadt was WRONG and if applied could have resulted in expensive damaged parts. He's usual act is to ignore if you question him about bs answer's and he continues with his bs answers until he is insulted enough so that he leaves. Sorry you folks have him.
Roy
I'm sorry for the folks that end up listening to "his" type of posting. Fortunately I don't think the Snoman is nearly as bad as the other few nasties that have come along in these newsgroups. Someone like Dean Dardwin not only gave a lot of erroneous information, but would attack you with a vengeance if you happened to point out his mis-information.
As you say, Snoman tends to simply ignore posts that stand him up and show him where he is wrong.
Ian
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