Are your transmissions similar to the AD4? I suspect they might be, after all these transmissions are based on the same mechanical principles?Hi, I've got exactly the same issue and just replaced fluids and solenoids, which did not resolve it. Did you end up finding a solution? I know this thread is 4 years old, but I'm hopeful!
I’ve repaired a few AD 4s. Prior to repair they had various problems including rough changes.
A specialist repairer (northern suburbs of Melbourne) told me that AD4s always slur or thump when changing gears - bull Tisch!
Paying special attention to clutch clearances makes for very smooth changes. Transmissions fluid, as long as it’s a recommended one, doesn’t matter much.
A clapped transmission often is smooth for a while after adding an additive (suspect the one I tried just increased or even improved viscosity.
Solenoids are easily checked with a multimeter. After all they are just electromagnets.
Don’t know about your transmissions but the AD4 was easy to overhaul with non specialised tools (as long as you leave the diff alone)