Gents,

Been there with the 3-4 squalk and a P0783 - the E Clutch is usually the first to go. I have done the fluid, filter, seals.

I even installed a used, known good TCM and solenoids. Turns out my TCM and valve body/solenoids were good because none of these items changed the issue.

It turned out to be mechanical - meaning find a used trans or get it rebuilt. I would up trading it in for my wife's new truck.

 

That sounds bad enough.... 64k miles and fluid changed at a dealer, owned previously by an old dentist.... Can't imagine what he did with the 6hp26 to make it a toast, these are supposed to last longer. My issue is a 5-6 squawk... it started as a squawk whenever I accelerated, then I changed the fluid, reset the adaptations and now it only makes a noise at 5-6....
I just realized that a very good ZF specialist, Peter Schmid is literally around the corner where I work. So I may ask his opinion, and if it's bad I'll drive this trans until it dies and will look for a use trans or Copart car with low mileage and pull from that+keep it for parts.