2007 Hummer H3 wont shift from second to third

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Nov 2, 2019 | 10:23 AM

Chris Catino

Thread Starter

Junior Member

Joined: Nov 2019

Posts: 1

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!

Nov 2, 2019 | 02:30 PM

bronxteck

Senior Member

Joined: Apr 2019

Posts: 3,188

From: BX NY North East

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.

Nov 2, 2019 | 05:33 PM

hummerz

Senior Member

Joined: Jul 2012

Posts: 8,979

From: C-Town

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

Nov 3, 2019 | 09:48 AM

wpage

Senior Member

Joined: Oct 2012

Posts: 869

From: Lewes Delaware

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.

Nov 4, 2019 | 11:39 AM

Doc Olds

Super Moderator

Joined: Jul 2007

Posts: 13,083

From: Boat Town USA MI

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.