More speedo problems...

Hi everyone, just replaced the speedometer on my series 3. I took the cable out at the transmission end to see what condition it was in. Seems absolutely fine but now I can't seem to get it back in properly so that it turns when the wheels are rolling.

I'm not really sure if there's any special technique to getting in. Because it's a rounded end it seems to me like you just stick it in and hope it works.

Any ideas would be much appreciated. Cheers.