So if the trigger of the sound can be automatically done and adjusted as you have it set up to do (% of movement before the sound kicks in) that would seem ideal?
Yes my thinking is along these lines but again this will need further evaluation when I have the time.
Ok, what I've done is create several new triggers. For those new to the TCB you can read more about functions and triggers
in the Wiki here.
There are two new triggers dependent on vehicle speed,
Vehicle Speed Increases Above x% and
Vehicle Speed Decreases Below x%, where "x%" is a percent you can specify. You could use these to start playing a sound (such as squeaking tracks) when the vehicle exceeds some speed, and then stop playing it again when it drops below some speed.
Another new trigger is
Brakes Applied. You could assign this to a braking sound for instance.
If you
download OP Config (or go to Help->Check for Updates if you already have it), you can see these triggers on the Functions tab.