Q: There's a bad smell after I rebuilt the transmission

Hi, and thanks for contacting YourMechanic. What seems to be happening is that your vehicle is having a parasitic draw (power drain with key off) within the electrical system of the transmission. Check the harness to the transmission and look for any wiring that is shorted to ground or any problems with any of the connectors on the transmission.

To determine what is drawing the power, take the ground cable off the battery and connect a digital volt meter to the ground wire and the battery post, but keep them separate. The digital volt meter will display a voltage reading. Go under the vehicle and unplug one thing at a time. Go back and see if the meter reads o voltage.

Once you have found the cable that is producing the voltage, then either the harness is shorted or the sensor or plug that it is plugged into needs replaced. Keep in mind, there may be more than one item in your vehicle causing the parasitic draw. The smell is probably wires burning or a sensor is burning as it drains the power.

I recommend seeking out a professional mechanic, such as one from Your Mechanic, inspect your electrical system to assist you with the diagnosis.