Multiple electrical issues after having the transmission and battery replaced

DANIELLE MAURER

MEMBER
2011 GMC YUKON
V8
2WD
AUTOMATIC
150,000 MILES

I just had a brand-new transmission put in my vehicle listed above Xl model. Started it up sounded great, got a half hour down the road and the gauges started bouncing all over and power locks kept going up and down and truck loses power. If I drive through it about 5-10 minutes, it goes back to normal. But once it is turned off it won’t start back up unless it sits for about 15-20 minutes. I also read something about ignition switches so just FYI I did replace that when everything started going bad so right now it has an AcDelco ignition. Also it does have a new battery as well. Please help I’ve been through the ringer with this thing I just don’t have another 3 grand or 6 months. (It’s been awful)

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

This does sound like a battery issue. So even though the battery is new, let's start with testing and proving the battery and alternator as still fine.

Any parts store should be able to do this free of charge. Here are guides that will talk about the type of testing that needs to be done:

https://www.2carpros.com/articles/car-battery-load-test

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Once we confirm that these are fine then we need to turn to a body control issue or even a bus related concern. This means we need to start with checking for codes and making sure the scan tool used will be able to pull communication or U codes.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Once we know if there are codes and the battery and alternator are fine, we can take the next steps, but we can go past this or assume they are fine and no codes.

The next thing we are going to address are body control module issue but more than likely this would not cause a derate in power. So based on all this, I suspect we have some info to go on based on the above test. Thanks