Hi, this is a follow-up a year later.
My shuddering during light acceleration and upshifts “re-worsened” shortly after the fluid change. I’m thinking that perhaps it didn’t really make much difference in the first place. My driving schedule at the time was short trips only, and the shudder is typically absent or greatly reduced with a cold engine/trans anyway. As soon as I started driving long enough periods for a full warm-up, things were “back to abnormal”.
I’m now up to 223,000 miles with the problem gradually worsening, so I guess I’m just going to drive it until it dies. It’s a shame, because even with all these miles the truck has no rattles, looks nearly new inside and out, doesn’t need oil between changes, and gets 23 MPG on a straight level freeway.
I’m also tempted to try the “Shudder Fixx” additive mentioned in a recent thread.