Momo Auto Gear Knob issue

[Chilli8]

Hi, I have just purchased a Momo gear knob to replace the plain black one on my auto (AU XR8). When I removed the old one, the plastic that covers the shaft extends about 60-70mm beneath the Handle to cover the shaft. The new one only extends about 10mm. Have I been sold a dud?

[BHDOGS]

There's a plastic cover between the shaft and the shifter like on the fairmonts

[Chilli8]

Thanks that makes sense now - might go back to the original one!