Be sure the vacuum supply line from the engine to the transmission vacuum modulator is not disconnected.
A "speed" sensor can affect the shifting of the trans.A "speed" sensor can affect the shifting of the trans.
check for a failed vacuum modulator or a vacuum leak to the vacuum modulator. It sounds like you are shifting on the governor or engine management unit.
Yes.
Bad spark plug wires affect many areas of your vehicle. However, gear shifting in an automatic transmission is not one of them.
transmission won't shift properly, and it may even go in limp mood to protect the transmission. A delayed shifting could be the culprit.
If you mean low oil or fluid in the transmission, then YES, it will lead to shifting problems. Low engine oil will not affect shifting.
check vacuum lines top passenger side rear of engine
No, the alarm will not affect the trans.
The real problem is manually shifting from gear to gear with an automatic transmission. If you are referring to the automatic upshift, there may be a problem with the EGR system or vacuum system.
O2 sensor or vacuum leak
If you are referring to the automatic transmission vacuum modulator, there isn't one. The shifting points are computer controlled based on different signals from various sensors.