[968 GUY]

Removing the steering wheel may be the best method for someone who has not removed the dash trim and gauge cluster.
It is not necessary if you are careful. I have left the steering wheel on and done repairs to the instrument panel several times. I did;nt the first time, messed up and triggered the airbag light on one of my 968's.
There are several places to get odometer gears. The place I bought mine from was very helpful and spent some time on the phone to walk me through the steps after replacing the gear and it still would not work. Mine had one broken tooth, I could never find the tooth, but my odom. is up and running.

I will try to include all that I remember him telling me. I do not remember the orientation of the gear, as in which way to put it on, you will see what I mean when you either recieve the gear, or disassemble the odom. So pay attention to how the gear comes off, reinstall the same way.

Make sure the broken piece(es) are not in the assembly.
wipe all the old lube off the assy.
gently blow out the assy., I used duster spray for computers, etc.
check the new gear for any burrs, remove as needed.
make sure the larger gear is in perfect shape...it mat be a good idea to order both if unsure, mine looked good.
make sure the new gear is replaced correctly.
make sure the gears mesh and are riding and turning well.

I was told that any resistance will keep the odometer gears from turning, that is why the lube should be cleaned off, it is old and has too much stiction for the small amount of torque it takes to overpower the assy, as well as the probable cause for the gear to become brittle over the yrs.
It took me two tries to get it right, but it works great, and only lost a couple hundred mi. on the odom. brfore I got it fixed.