Hi,
I've been scanning the forum looking for some responses on an issue I'm having. I just bought a 2009 Vibe (in December 2022). When I drove it off the lot, everything was running normally. Then the old battery died, so I took it to an Advanced AutoParts to have a new one put in. The guy put in a 26 group battery and took a long time doing so. In all honesty, it didn't really look like he knew what he was doing. He struggled to get the old one out and the new one in. Ever since then, my car has shifted really hard in-between 1st and 2nd gear. I've taken it to a mechanic, a Chevy dealership, and most recently a transmission mechanic. They've scanned it for electrical damage and didn't find anything. Yesterday, the transmission mechanic cleaned off/polished the battery terminals to make sure the battery is grounding properly.
One thing I've learned is that a group 26 battery is a "smaller" battery. I realize it might be a fool's hope, but if I replace the battery with a group 35, might this fix the problem?