Newbie with a question

[Stoad]

I have a problem with a 2001 chevy 1500 z71 extended cab. There is a noise comming the transfercase area. what i thought to be the u-joints. They are in desperate need of replacing which i am in the process of doing now. While i was trouble shooting the noise problem i discovered that the front drive shaft turns continually in 4hi or 2hi. Is this supposed to happen, or should I start taking out the transfer case for repair? I called my local GM dealer service department and they told me that the shaft always turns, anjust the front axles lock up when 4wd is engaged. I looked at another 2001 and the drive stayed stationary. could you please give me some insight.

[vinniej]

Check the 4x4 system. if it is the auto 4x4 it shouldn't turn. If it is just the regular system it will turn. On the standard systems when you put it in 2wd, it disconects one side of the front axle (one front wheel stays connected to the drive shaft) and that is why the shaft still turns.

 

I'm not exactly sure on the auto system how it works, but I think it actually unlocks both front wheels. That would be the reason the shaft doesn't turn.

 

Someone correct me if I'm wrong, because I have been wrong before.

[Stoad]

Thanks for the info . It is the push botton with auto 4Wd. so i suspect it will be a problem with the transfercase. time to break out the wallet I guess. Any further insight would be appreciated.

[vinniej]

Thanks for the info . It is the push botton with auto 4Wd. so i suspect it will be a problem with the transfercase. time to break out the wallet I guess. Any further insight would be appreciated.

 

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I would also ask another shop and see what they have to say about it.

[Stoad]

Thanks. taking your advise to contact another shop I phoned the third gm service shop in my area and was told that if the truck has the auto 4wd option that the transfercase does disengage the 4wd, but there is enough drag on the clutches to turn the shaft constantly. This being said the same drag allows enough force that you could not stop it from turning. I changed the ujoints and the problem is fixed. I have to take the last advise of the shop and belive that the shaft on my truck will constantly turn.

Thanks

[vinniej]

Thanks. taking your advise to contact another shop I phoned the third gm service shop in my area and was told that if the truck has the auto 4wd option that the transfercase does disengage the 4wd, but there is enough drag on the clutches to turn the shaft constantly. This being said the same drag allows enough force that you could not stop it from turning. I changed the ujoints and the problem is fixed.  I have to take the last advise of the shop and belive that the shaft on my truck will constantly turn.

Thanks

 

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Yeah, I wasn't sure about the auto system, but I know now.