@NickTransmissions thanks for your quick response and information! Where are you located by the way? So to respond in order:
-No check engine lights or codes according to a scan with the GM Tech2.
1. Adapts (or lack thereof) resulting from either mechanical issues, programming changes -- a fast adapt may correct the issue) or TEHCM-related problems)
Can I do this with the Tech2? Is it worth using the Tech 2 to check the solenoids that I found in the unit?
2. Torque converter clutch apply and release out of synch with clutch apply and release timing due to either tuning or converter clutch or internal components wear
> did the tuner do anything in the TCC tables to change the apply/release speeds or mess w/the torque management?
I have downloaded HP Tuners and have my tuned file but I have not gotten the base file to compare it to. However, in comparing it to another yukon file I found, it appears he did change some things in both the apply/release and torque management. However, I had the problem before he made any changes anyway. He improved it slightly.
3. Wearing/worn compensator feed regulator valve - this valve is specifically tasked with 'smoothing' shift feel (laymen's explanation)
Is this in the pump or the valve body?
4. Wearing/worn torque converter clutch regulator valve (lower valve body), TC control valve or limit valve (pump)
Again, would a Sonnax valve body correct this?
> Consult your tuner and get his thoughts on performing a fast adapt relearn to see if simply resetting the TCM back to factory settings fixes the problem (simplest option, least LOE/expense)
Is this necessary if A, I can do it with the Tech2 or B, since I had the problem before he made any changes? Of should i reset to factory settings and then do a relearn?
> If a fast-adapt doesn't fix the problem, I would pull the valve body and TEHCM and replace w/a Sonnax reman and overhaul the TEHCM (verify it's in serviceable condition prior to overhaul)
So this would be the Sonnax reman valve body and then test the electric solenoids via the Sonnax rebuild videos before replacing the pressure switches?
> If you were local to me, I would
test your valve body assemblies (upper and lower) to confirm my hypothesis so as to avoid spending money if you don't have to (i.e. the problem is the converter or valves in the pump, not the valve body)
I would think if it was the converter i would have issues at other shifts, no?
> If the entire valve body passed the testing and the tuner didn't see anything problematic with the TEHCM or the values in the various transmission shift strategy tables, including the TCC table then the next step would be to pull the unit and test the pump cover valve trains then perform a teardown and inspection of the main case, focusing on the 2-6 clutch pack, 1-2-3-4 clutch pack and low-reverse clutch pack as all are involved in the 3-2 and 2-1 down shift process.
Are you familiar with HP Tuners that if I sent my file to you it would be advantageous or not? I am slowing doing research to try and confirm this but its beyond my quick understanding. I am going to try and meet with the tuner to ask him some questions but I do not want to be a pest about it either.