Right my Sierra XR4x4 has some vibrations and whining noises present.

Upon inspection there is witness marks where spacers have been fitted between the centre bearing and the tunnel floor in the past.

The question is how thick are the spacers meant to be?

We have packed it up to 9mm already and the sound is going away slightly.

Doing research and people are saying 13mm or 1/2".

I have until the morning to get the spec before I am back at a mates garage with it on the ramps.

Any help is greatly appreciated.

Rob