46re transmission help

Ok I have another question. I almost have the brake lines finished up so I can test drive and try and diagnose this transmission. Here is my question. Since the truck isnt insured, tagged and inspected I cant really drive it far so I'm just gonna drive up and down my road to test it out. I want to drive it cold and see what it does and then get the transmission up to temperature and drive it and see what it does. Since I can't drive it far does the transmission build temperature just idling? Can I put it in drive and let it run for say 30-45 mins ? Will that raise the temperature of the fluid just like driving it?
Another question
@Jadaharabi said the 46re is electricity shifted I have noticed there are several things electrical on this truck not working properly. One the tachometer isnt working the wiper sprayer isnt working and the wipers dont work right (fuses are good I checked) is there anyway possible these problems are linked? Something electrical is wrong and causing this stuff not to work? I'm sure how the tack and transmission would be connected but I figured it's worth looking into. Thanks