Transmission only get 1 and 2 gear sometimes 3rd?

2002 CHEVROLET IMPALA
100,000 MILES • 3.4L • 6 CYL • 2WD • AUTOMATIC
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CONCRETE CRAIG
Have to unhook battery after use or lights and door chime come back on in 30 minutes and usually after reconnecting and driving have to immediately stop unhook battery and usually twist cables to get it to touch right sometimes stopping 2 or 3 times before it will start shifting and then I only get 1 and 2 gear sometimes 3rd.
Sep 27, 2025 at 11:27 AM
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KRAKENAUTO
  • ✓ASE Certified Mechanic
  • 40 POSTS
  • ASE Certified Mechanic
It sounds like a potential BCM or even a bad ground issue, which was common problem on these. I'd try to clean and tighten your battery terminals first. If it continues, use a scan tool and see if you can see any U codes (communication) or a transmission control code.

Try the above first and let me know if that helps it at all. If not, we will continue troubleshooting.
Sep 27, 2025 at 7:40 PM
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