Nissan Patrol 4x4 (Africa)

I have a shudder on the steering around 100 km/h and its both ways, so when you brake, and when you accelerate. I can't seem to solve this issue.

1) Wheel bearings (first mechanic I took it to said the wheel bearings were a bit loose.) - This did not fix the issue.
2) Wheel alignment - This did not fix the issue.
3) Wheel balancing - This did not fix the issue.
4) Tyre rotation - This did not fix the issue.

Vehicle is a Y61 Nissan Patrol with 65k km on it.

Any idea what it could be?

Any advice would be much appreciated. Thank you.

I presume it is the fabled "death wobble". Have them check all the bushes.

Also - do not discount the tie-rod ends, steering damper etc. As I think of this the list gets longer...

Please provide feedback when it is sorted.

What Ian said, plus kingpin bearings.

Primary suspects are wheel bearings, steering joints, panhard rod bushes and kingpin bearings, in that order.

First, lie under the car while somebody moves the steering wheel side to side, and feel for movement anywhere. Don't neglect the steering box itself. If you don't find anything, use a crowbar to lever on the panhard rod. If that seems fine, jack the front end up and try to rock the wheel while holding it top and bottom (wheel bearings) and side to side (second check on everything you just checked). If you still haven't found anything, remove the kingpin bearing caps and take out the thinnest shim on each, and see if that helps.

Took it to G-tech for a major service yesterday, and they resolved the issue by adjusting the wheel bearings.

The previous indie and Patrol specialist as stated did the same, but the issue remained. Guess they just had an off day as we all do.

Thank you for all the feedback and help.