On a 94 E320 I want to replace the shift lever knob and shaft. I have removed the plastic surround and the center console wood. Now I am looking at a black box the shift lever goes into. The top of the box somehow comes off. That top piece is about 1/4" thick has the gear letters on one side and the shift gate on the other.How does that top piece come off? It has to come off to gain access to the nut that holds the shift lever in place.