2007 Hummer H3 wont shift from second to third

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11-02-2019, 10:23 AM

Chris Catino

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Join Date: Nov 2019

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2007 Hummer H3 wont shift from second to third

2007 hummer h3 122k miles, wont shift from 2nd to 3rd, replaced tranny with a used one and its doing the same exact thing! if there reprogram or something that im missing? 2 tranny's doing the same exact thing? help!

11-02-2019, 02:30 PM

bronxteck

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Join Date: Apr 2019

Location: BX NY North East

Posts: 2,628

maybe it's an electrical issue with the harness or connector. you would have to connect a scanner that can interface with the transmission to see if she is shifting or if it can activate your shift solenoids.

11-02-2019, 05:33 PM

hummerz

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Seriously, the transmission was not shifting from 2nd to 3rd, so you replaced the transmission?

11-03-2019, 09:48 AM

wpage

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Join Date: Oct 2012

Location: Lewes Delaware

Posts: 705

Quote:

Originally Posted by hummerz

Seriously, the transmission was not shifting from 2nd to 3rd, so you replaced the transmission?

Ouch, bet that hurt...

Next time ask here first for good resources.

11-04-2019, 11:39 AM

Doc Olds

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Join Date: Jul 2007

Location: Boat Town USA MI

Posts: 12,189

The 2007 H3 Auto Trans is controlled by the PCM. The PCM tells it when to shift and to what gear. You likely have an electrical issue.

Scan it for codes and post whatever codes it may have stored here.