I asked for help on an issue about possible transfer box problem, which Treginginco helped with. But my VW dealer informs me that mixing new with existing used tyres (not changing all tyres. Two new ones 10mm old ones 4mm) can cause transfer box problems, and the juddering I initially felt was the start of this problem. Luckily I traveled only 10 miles, and have now been informed that when all the tyres are changed everything’s fine. Im now thinking of getting a Range Rover !