Same as me, truckers know how to drive don't they?I tried this today but it went against the grain. In normal running I dont think I ever need to change down from 4th to 3rd.
I tend to change down in blocks as I am used to driving 44 tonne vehicles with around 16 gears.
The probable reason for the judder (bearing in mind how low geared 3rd is) is that the road wheels are going too fast.
I wont change into 3rd unless I was travelling at less than 15mph.
Having said that ,the last time I changed down from 4th to 3rd was when I had a four speed gearbox..(1983)