front driveshaft vibration (gearbox side)

[Busterqkh]

I thought I'd post about this as the problem I'v had has taken way too much diagnosing.

basically my 2009 1.4tdi bluemotion car started to develop a bad vibration from what felt like the front nearside (UK righthand drive) driveshaft. the problem was worse when travelling up bumpy hills in low gears, on very cold days no vibration, on very hot days it was almost guaranteed.

I changed the driveshaft, the steering knuckle, the bearing (twice), the ball joint, checked the wishbone, the track rods and ends but nothing cured the issue. it went through a UK MOT like this (MOT guy changed anti roll bar link) so the issue presumably didnt show up on that shaker plate thingy that they use now.

eventually I found a video online that seemed like a similar problem so I changed the lower gearbox mount, slightly better but still had the problem.

this morning I finally got to the bottom of it when I changed the gearbox upper mount and that has cured the problem outright, basically the gearbox has been sagging at a horrible angle and clearly upsetting the driveshaft.

I could'nt find anything about this problem online so thankfully its probably fairly uncommon, but maybe this post will help someone having a similar issue