Thanks for posting the picture.
As I only have 2 small wheel ramps I was unable to find the modulator, but with your pic, I knew exactly where to look!
I have finally managed to solve my gearbox juddering at 1,500 rpm just before it changed up a gear with a load thud.
All I had to do was adjust the modulator by one 'segment/click' and it changes gear as smooth as silk.
Thanks again for the picture.