Q: Transmission problem after alternator replacement

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Hi, I had an alternator replaced 3 weeks ago. Afterwards, I noticed that the transmission couldn't shift to higher gears when driving at higher speeds. RPM was also very high. This persisted for 2 days and then went away. Just the other day, the transmission problem reoccurred while I was driving. The car then came to a stop and I was not able to get it accelerating again. I powered off the car and started it back up and was able to drive at a low speed. I've been finding similar cases online where a low battery or a bad alternator caused similar transmission problems. The explanation is that not enough voltage is being supplied to the electronic transmission control, which leads it to send out no signal or a wrong signal. This then triggers the vehicle to go into limp mode. Given the symptoms and the transmission problem coinciding with the alternator replacement, is it possible that this could be a potential cause for my transmission problem? Thanks!

My car has 113000 miles.
My car has an automatic transmission.

Hi there. Why was the alternator replaced? Was the battery tested with a digital tester that provides current voltage, cold cranking amps, and state of health? If not, I suggest having that battery tested. A bad cell inside the battery can wreak havoc on electrically controlled systems; especially computer controlled systems. This cell can create voltage spikes and dips where there should be none. I suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with an electrical problems inspection.

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