Hi and thanks for using 2CarPros.
First, please understand this specific model isn't available in the US. However, I have technical information for the Mitsubishi Montero which is to be the same vehicle.
The fuse that keeps blowing is a concern because if how much current needs to flow for it to blow. With that in mind, there has to be a direct short from the power supply.
As far as the transmission, it makes no sense to me that a blown alternator fuse would cause transmission issues. However, if there is low or not enough power, electronics will begin to fail which is what I believe you originally experienced. Regardless, once the power is restored, the electronics should return to normal. That leads me to my next thought. Since the speedometer wasn't working, that tells me the output speed sensor wasn't working. The speed sensor is responsible for making the speedometer work. If it fails, the transmission will most likely not shift correctly. Is that what was happening?
With all of that in mind, and the idea that other things are still not working, I am going to first suggest you check the fuses related to the components still not working
Next, on my schematics I see a 100 amp fusible link for the alternator. See picture 1 Is that what is being replaced? If it is, has anyone checked the alternator itself for a short?
If you lose power from the alternator once the vehicle is running (blown fusible link) there will be electrical issues until the battery is run dead.
Let me know.
Sunday, March 3rd, 2019 AT 8:23 PM