[chris_seven]

It seems to me that the gear shift needs to considered as an complete structure rather than be broken down and analysed as individual parts.

With the car stationary the gear lever and coupler need to be able to be adjusted to deal with axial, radial and parallel misalignment which they can clearly do otherwise they could never be fitted.

Once the system has been installed and adjusted and the car is moving then there are movements of the engine/transmission that need to be dealt with and I think that the standard system allows this to happen:

The ball and cup on the end of the gear lever will allow the engine to rock or shuffle laterally.

The angular movement of the gear coupler will allow the engine to bounce up and down or rock vertically

The slot in the coupler bush will allow fore aft movement.

I do agree that standard couplers do seem to have too much clearance but the Delrin bush eliminates these issues and is very cost effective.

I am not convinced that expensive Aeropace standard UJs are needed. A steering UJ for a Group4 Escort for example is about $30 and seems to last for about 10 years of competition before it wears out.

The other minor point is that any change to the coupler that eliminates the axial clearance must result in some ‘wag’ on the gear lever.

The slot in the standard coupler bush allows the engine to shunt back and forth or deal with any change of axial position due to some other complex motion.
If you remove all of this axial clearance then small fore/aft motions must wag the gear stick slightly as there is no other way of allowing for this movement.

If the gear lever has a 5:1 ratio than the+/- 1mm movement of the standard coupler translates to about a total of 10mm movement at the gearknob which is a small percentage of the total movement in a first to second gearshift (less than 10% ?)

If you fit the solid RSR engine mounts this wag will virtually disappear and a solid bush would not be noticed.

I think the secret is to maintain the gear couplers and gear lever bushes and to keep them clean and in good working condition.
From what I have seen these parts and the pedal boxes are the most badly neglected areas of most 911s.