no i dont think so....how would I do that^^^

 

with an ohmmeter -- should be a function of your multimeter which I assume you have since you checked the voltages at the connector.

 

Yes I do have one. Where do I test this at?

 

With 140,000 miles on the car and you did not put them on it, I would get the transmission serviced before I went one step further. While larger than OEM rims and tires will to some effect cause some difference in operations of the way the car was designed to work, when things are in good shape those differences are invisible.
The car does not know what size wheels and tires are being used. A transmission needing service can fail in a number of ways. Or act as if it is a failure mode due to tranmission fluid problems.
Guessing what expensive parts might be broken or part of the problem does not help fix things, but just throwing parts at it can also not help fixing but can be expensive.
So deal with getting the transmission serviced before you throw anymore money at things you really have no idea what effect that they have.
Do it your self for the cost of materials and a filter or spend about a C note in having it done.