While doing a test runs in our beloved 928 we notice a strange anomaly while shift gears. If you are wondering what shifting gears is, well, it is something real men and the most desirable women in the world do. So now that this is cleared up... Like I said a strange anomaly. The shifter decided it no longer wanted to adhere to the ridged constructs of society and decided to stick it to the man. This man! So the shifter was basically free go anywhere and yet refused to be a productive member of society, I mean, the transmission. After a little investigation it became apparent that the issue was with the angular joint on top of the torque tube forward of the shifter assembly. Image 1 shows the cup portion of the offending joint. Once we got the car on the ramps and took a look it was very clear what the problem was. The angular joint is made up of three component. A ball, an metallic cup and a bushing that inserts into the cup. After thirty years the bushing has broken down and instead of looking like Image 2 it looks like Image 3.
You can see in Image 3 that the bushing has basically broken into two pieces and is half missing. The half that is missing is the half that locked the cup on the ball. So there is two paths to to do a OEM repair here. The first is to purchase a new angular joint assembly (Part# 928-424-005-01) for about $100 or if the cup is still in good shape just replace the bushing (Part# 928-116-145-03) for about $20. The easier method is to simply spend the extra money and replace the assembly. (See Image 4)
The problem is that it is damn near impossible to push that bushing into the cup without removing the cup from the tube guide (See part 3 in Image 1) and since you need to remove it you may as well immediately replace it with the new assembly. To give you an idea of just how futile it is have a good look at Image 5. There you can clearly see how little space you have to work with while the cup is still attached. You actually cannot even get a straight shot at pushing the bushing in. Every time you attempt to push it into the cup it will skew on you forcing you to realign and start again. So after taking the cup off you still need to then manipulate the bushing into the cup while your blood pressure sky rockets and you begin uttering a line of expletives that will get your kid through college on the swear jar proceeds alone. This in itself makes the complete replacement more cost effective. So save yourself the headache and financial duress and replace the entire assembly.
There is an alternative that makes future replacements unnecessary. A replace once and be done with it version. It is an alternative part offered by 928 Motorsports called a Precision Shifter Ball Cup which can be seen in Image 6. This option will run you approximately $100 as well with shipping factored in but this option is designed for the endurance and reliability required by motor sports so for the typical driver this will be the last time you need to look at this issue. This is definitely more complicated than the complete OEM assembly replacement given the tight space you will be working in but long term it is a solid option. In fact this was the option we chose to move forward with. Given the nature of the things we will be doing with the car we wanted to make sure reliability was maximized. Once we completed the install and before putting back in place all the heat shields, support members and reconnecting the oxygen sensor we checked to make sure that the shifter was doing it's job properly and voila! The shifter was now a productive member of society...I mean the transmission once again.