Brothers of The Benz.
I've had my old sled for 14yrs. and it too is a slow shifter when cool/cold and a solid shifter all the time. Not smooth as silk but solid like a rock. When He shifts you can always feel it positive solid no slipping between gears.
Isn't it strange that when orderring a complete set of service manuals that a transmission manual isn't part of the set?
Is the transmission included on the new CD?
I don't use synthetic fluid, but as I've said as part of my maintaince program is to pump the sump empty and refill with MerconIII with ever engine motor oil change. Except for the intial pan removal when He was a Baby, and that was to remove any residual stuff from manufacturing, the pan and filter have never been serviced. Who knows, the filter may be almost stopped up?
The three fresh qts of fluid seems to give him a cool drink, so to speak.
Anyway what ever The Spiderman is doing appears to work.
Fresh fluid either all at once or a little at atime is what these rascal need!
Happy Trails Beep Beep from Donald The Spiderman in Houston!!!