4wd shifting

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nzhoppy1
Posts: 3
Joined: Sun Jan 25, 2015 11:17 pm

4wd shifting

Unread post by nzhoppy1 » Sun Jan 25, 2015 11:39 pm

97 GMC 5.7 auto. 4wd. Can't shift from 4wd back to 2wd ?

 

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carriedi
Posts: 2268
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: 4wd shifting

Unread post by carriedi » Mon Jan 26, 2015 11:53 am

you should check your 4wd module. have it scanned and see what it going on. Have you checked to see if the transfer case is staying in 4wd or is the front axle staying locked? The front differential actuator might be stuck in the engaged position while the transfer case is in 2wd. Or the transfer case could be stuck in the on position. You will have to find out which part is not turning off.
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nzhoppy1
Posts: 3
Joined: Sun Jan 25, 2015 11:17 pm

Re: 4wd shifting

Unread post by nzhoppy1 » Mon Jan 26, 2015 4:58 pm

Where is the 4wd module located ?

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carriedi
Posts: 2268
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: 4wd shifting

Unread post by carriedi » Mon Jan 26, 2015 8:44 pm

the transfer case control module (TCCM) is located under the dash mounted to the steering column support bracket. it's just a control module. It doesn't have any serviceable parts in it. why do you ask? Have you scanned it? What are the codes? You scan it through the ALDL, same place you scan the engine, ABS, airbag, etc.

have you found out if the transfer case is stuck in gear or if the differential is stuck locked in? You know, you could have a bad encoder motor...

need more info, feedback to say what to check for...
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