To second what Sven's says:

The new piece (readily available at your dealer, I had to buy one recently for a car I sold) just snaps into the trip odo shaft in the bottom of the speedo.

There are rather small phillips screws holding the speedo to the white plastic cluster backing. Be careful, go slow, they're self-tapping screws that have probably never been serviced; one especially defies attempts to turn it easily. Locate and use the right size screwdriver- if they strip the heads out, it becomes a more difficult job.

Be careful of the speedo needle- you shouldn't have to mess with it at all, because you're not really taking the speedo motor apart or anything but don't lay it on it's face or snag it on anything- it is fragile plastic.

The flat leaf springs at the very bottom of the speedo provide the detent you feel when you push the reset. They can be bent right out of the way with no ill effects and it'll spare your new reset button from the same fate. I broke two of these after I got my 92 240, then did this mod, so the current one is happy.

Good luck and just take your time with the job- and keep the steering wheel straight when pulling the cluster, to make life easier. Expect a little bit of tightness at the top of the dash as it comes out.
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::: Rob Bareiss, New London CT ::: 92 244 M47 212K ::: 90 745GL M47 275K ::: 90 745T AW71 213K ::: 90 745T Parts Car ::: 88 245DL SOLD! ::: 84 242DL Project ::: 70 VW Bus ::: 70 VW Pickup Project ::: 71 VW Notchback :::