think there is a diff between the tca's but not sure what.
the speedo is driven off the front diff (i think) wouldnt recommend checking with drill as it can damage cables, if you whip the cluster out and move the car at about 10mph you should see the cable turn, it is normally the drive that goes on most cars rather than the speedo itself dont know if it is replaceable but most are a plastic worm drive and wear the teeth off.

note it is in front diff on a 4x4 saff think it is fairly easy to get to