So I went through my transmission valve body today.......
I did the Sonnax zip kit and EDS solenoids today. From what I've read debris in the solenoids and their screens is a common source of shift quality issues. There's a local shop in Houston who will flush and flow test them on a machine for $250. I opted for new EDS solenoids, as the newer solenoids are improved parts. As far as the 5th gear surge at 35-40mph, from what I've gathered it's due to pressure loss in the Clutch A control pressure regulator valve bore. I've heard some claim new solenoids addressed it, but the general consensus seems to be they are not the source of the issue. The zip kit addresses this circuit, although excessively worn valve bodies may need an oversized valve.
Beyond the just purchasing the zip kit, you'll need to get the part number off the valvebody separator plate to order the correct new one. The repair instructions mention you can reuse the plate if the gasket material stays intact, but it's pretty much guaranteed to come apart(mine did). You'll need the bridge seal adapter and the 4 round seals are recommended as well. I replaced the pan/filter and fluid(I used over 9 quarts to refill after the repair).
I cleared adaptations, it took about 10 miles of driving at various speeds for it to completely adapt. The 35-40 5th gear surge is gone, and shift quality is like new.
Last edited by meangreen94z; 12-13-2014 at 10:56 PM.