That's no problem.

Obviously you need to get the box out.



1. Remove the shifter. Make sure the box is in neutral.

2. The shifter "block" is mounted to the shifter shaft by a retainer pin. Punch this straight down and it will come undone. Use a suitable punch for this.

3. Undo the tailhousing bolts (15mm socket)

4. As you pull the tailhousing off, make sure to slide the shifter block off the shifter shaft simultaneously. It has a spring and ball under it so don't loose those. You will have to push this block down a bit while you wiggle the tailhousing off.
Remove the sealant remnants.

5. Now you have the output shaft in front of you and its easy to remove the speedo-gear. Replace with new, reverse the process. Apply sealant between the two housings.