# 92 gmc 4wd problems

**URL:** <https://forums.speedlife.net/t/92-gmc-4wd-problems/204390>\
**Category:** PittSpeed Automotive\
**Created:** [December 21, 2009, 10:54am UTC](https://forums.speedlife.net/t/92-gmc-4wd-problems/204390 "2009-12-21T10:54:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![SupraSean](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/suprasean/32/6062_2.png) [@SupraSean](https://forums.speedlife.net/u/SupraSean)\
**Post date:** [December 21, 2009, 10:54am UTC](https://forums.speedlife.net/t/92-gmc-4wd-problems/204390/1 "2009-12-21T10:54:12Z")

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ok i have a 92 gmc 1500 with auto locking hubs, and i tried to use the 4wheel the other day, i threw it in neutral and put the transfer in 4 high, the stick feels like it engages but front wheels DO NOT engage, on the flipside, when i put it 4 LO, it goes in and the 4 wheel works. as a side note when i put the transfer in neutral, you can here a faint grinding noise. is it possible that the linkage is maybe off? or are there seperate signals for the 4 high and 4 lo to engage the hubs? any advice would be golden Thanks.

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**Author:** ![BlkP42E](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/blkp42e/32/5938_2.png) [@BlkP42E](https://forums.speedlife.net/u/BlkP42E)\
**Post date:** [December 21, 2009, 12:48pm UTC](https://forums.speedlife.net/t/92-gmc-4wd-problems/204390/2 "2009-12-21T12:48:08Z")

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pewter is your man on this question

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**Author:** ![sinim](https://avatars.discourse-cdn.com/v4/letter/s/54ee81/32.png) [@sinim](https://forums.speedlife.net/u/sinim)\
**Post date:** [December 22, 2009, 7:25am UTC](https://forums.speedlife.net/t/92-gmc-4wd-problems/204390/3 "2009-12-22T07:25:52Z")

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I’m not sure what GMC was using. I had a '90 4Runner that had a similar problem and used vacuum lines to engage the 4wd. Turns out they had all been ruptured and it was a simple fix. Just something to consider. I never tried putting the transfer in neutral though, so I can’t tell you anything there.

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**Author:** ![SixSpeed454SS](https://avatars.discourse-cdn.com/v4/letter/s/e19adc/32.png) [@SixSpeed454SS](https://forums.speedlife.net/u/SixSpeed454SS)\
**Post date:** [December 22, 2009, 9:38am UTC](https://forums.speedlife.net/t/92-gmc-4wd-problems/204390/4 "2009-12-22T09:38:59Z")

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Fullsize GM trucks used a fully electronic front axle. They are plagued with issues & are relatively simple to fix. There were at least 3 factory upgrades to the front axle solenoid, and they still have issues.

I have seen on more than one occasion that the switch on the transfer case is bad & will not allow the front axle to engage. You can test it easily with a continuity tester. It should be open when in 2wd & closed in 4wd. If the 4wd shifter isn’t adjusted properly, the switch may not engage either. This switch needs to be closed to tell the front axle solenoid to engage. I would look here first before spending any $$. A simple toggle switch can bypass it for a temp fix.