Id invest in one. Autel is prob the best bang for your buck and should give you all the capabilities you need as a DYIer. Not having a scan tool puts you at a huge disadvantage; they typically pay for themselves in one to three uses vs going to a shop to have them use their scanners and charging you $$$ for that service.
You need to find out if the PCM is commanding the TC off or if the TCC is releasing when it shouldnt be. If the TCC duty cycle is at or near max in third or fourth gear while cruising and slip speeds are higher than 10-15 rpm then there's def a problem. From there, you need to find the source of the problem.
The list of suspects are the following:
- TCC solenoid/harness (you replaced this - what tcc solenoid did you buy?)
- Worn TCC regulator valve (valve body) - very common in these transmissions
- Worn TCC apply valve (pump) - less common but i see it from time to time on the vac tester
- worn 2-4 band
- worn/failing 3-4 clutch pack
- Worn torque converter clutch and/or failing torque converter
Given the amount of miles on your trans, I'd begin saving for a rebuild if you havent already done so.
Are you open to learning how to rebuild it yourself?
