4WD will not shift into 4Hi

30

Asked by Jaydub61 May 11, 2016 at 03:24 PM about the 2002 GMC Sonoma SL Ext Cab 4WD

Question type: Maintenance & Repair

Will shift into 4Lo and then into 4Hi, but not directly to 4Hi.  Have disconnected battery cable for 5 min to reset TCCM - same symptoms.  Seems like if it were vacuum line issue, it would not shift to 4Lo???

1 Answer

30

Will attempt to clarify my issue and question: 2002 GMC Sonoma with 3-button shift on dash - 2Hi, 4Hi, 4Lo Was able to shift directly from 2Hi to 4Hi, but stopped working last year. It can still shift from 2Hi to 4Lo (while stopped and in neutral) Once in 4Lo it can then shift into 4Hi Also have to be stopped and in neutral to shift from 4Hi back to 2Lo, then from 2Lo to 2Hi. It has basically lost the ability to shift on the fly. My question - DOES THIS SOUND LIKE A KNOWN ISSUE WITH THE TCCM? Research shows the most common problems to be vacuum lines, vacuum actuator or TC vacuum switch (ball stuck). My logic is that if the problem was with the vacuum system - it would not shift to 4Lo (or anything) --- maybe this is not good logic? I hate to just start changing parts and hope I find it. I'm unemployed at the moment and can't afford to pour lots of money into this truck. Special thanks to ANYONE for helping me out with some advice or benefit of their experience.

3 people found this helpful.

Your Answer:

CarGurus Experts

  • #1
    parkle
    Reputation
    1,090
  • #2
    Mike Bonnell
    Reputation
    660
  • #3
    James Mayfield
    Reputation
    410
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet S-10
2 listings starting at $12,975
Used Chevrolet Silverado 1500
222 Great Deals out of 5,891 listings starting at $2,975
Used GMC Sierra 1500
148 Great Deals out of 7,070 listings starting at $3,950
Used Nissan Frontier
24 Great Deals out of 891 listings starting at $5,998
Used Ford F-150
327 Great Deals out of 15,257 listings starting at $3,295
Used Ford Ranger
16 Great Deals out of 1,488 listings starting at $2,888
Used Dodge RAM 1500
7 Great Deals out of 67 listings starting at $4,000

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.