Body linking

[nige777]

Hi,
I'm developing a training environment where the user must operate a fork lift truck and be able to get on and off. I have set up the fork lift using physics joints and motors so that it "behaves" correctly, which it does-to a certain, pretty much.
Firstly when I pick up the objects with the forks that need loading and stacking (cages made with collideBox's top and bottom) there is a noticeable 'wobble', to the point when it looks unrealistic. Is this a trade off of using a bunch of dynamic physics shapes held together with physics joints?
Secondly when linking the viewpoint to the fork lift I loose control of the head, I presume it is the head_ori that is linked is it? I have tried using setMask but to no avail.I have tried using this:

#TIMER
def onTimer(num):
#    #The timer with the id 'num' has expired
    if num == 0:
        #Link matrix of runners to forks(turning)
        turn = run.getMatrix()
        turn.preTrans(0,1.6,0)
        view.setMatrix(turn,viz.BODY_ORI)
        
viz.callback(viz.TIMER_EVENT,onTimer)
viz.starttimer(0,viz.FASTEST_EXPIRATION,viz.FOREVER)

which does what I want but produces REALLY bad juddering when the truck is moving.

Am I missing something really simple here?

Regards

Nige