Hope you don't mind me adding to the thread.
This shows an odometer correction due to a gauge cluster swap on a 96. Original mileage 111K. "New" gauge cluster had 250K. The 96 has a mechanical odometer but it's driven electronically instead of via a cable. The gauge cluster I purchased was advertised as coming from a 96 so it was a same-year swap.
Follow TMXONR's directions for removal of the old idiot light panel from the dash. The only real difference is that instead of a speedometer cable there's a second electrical plug to undo.
Remove the 4 screws on the front of the gauge panel and remove the clear plastic cover and gauge surround. If you have a trip odometer you'll need to pull the plastic knob off the trip odo reset shaft.
The speedometer is held in via 3 screws on the back of the cluster.
Those screws make the contact between the speedometer and the flexible printed circut so don't loose them.
At this point the speedometer will fall out from the front as a unit. If the old speedo unit is acceptable you could just swap the old for the new. In my case the new unit has a trip odometer so I wanted to reset the new unit to the correct mileage.
Remove the 3 screws holding the white plastic panel on the back of the unit.
It should just lift away. There's a circut board under that held in by a couple of tabbed shafts. Gently pry the shafts back to clear the tabs and the board should come out.
The odometer wheels are turned by a small gear unit that's held in with a couple of tabs and a small melted plastic button indicated by the screwdriver below. Use something sharp to trim the edges of the melted button so the gear drive unit can be removed. Bend back the tabs (carefully, they do break) and the gear drive unit should come out.
Tabs where the red lines are - the top one is broken (this is the old unit.)
At this point the 10ths wheel will turn freely. Rather than turn the 10ths wheel backward to get from 250K to 111K, even using a drill I removed the number wheels from the unit to see if I could manipulate them to change the rest of the digits. Here's how to get the number wheels out:
The shaft holding the wheels is held in place by a couple bits of melted plastic. Trim the melted plastic till you can pop the shaft out. Don't carve too much, you'll want a good socket when putting the thing back together.
To get the number wheel completely out of the assembly remove the two screws from the front of the speedometer. I tried to gently remove the speed needle to completely remove the face but it wouldn't move. In any case the face tilts forward so there's enough room to get the shaft and number wheels out.
The number wheels are held on the shaft with what appears to be a brass pressed on washer on the high number side. You can see it in the picture above. I tried to get that off and started to bend the shaft so stopped.
However, if you have your old unit the easier action is to remove the number wheel from that and put it in the new unit which is what I did.
Otherwise you'll have to disassemble the number wheel or use a drill or dremmel to turn the 10ths wheel till you get it where you want. Post pictures if you take the number wheels apart.
Reassembly. There are some flat pieces of metal between each wheel as indicated by the red lines in the picture above. These have a finger that engages part of the plastic housing so make sure those are in the right place.
I put a bit of epoxy at the ends of the shaft to replaced the retaining plastic (the shaft doesn't turn) and over the trimmed button on the gear drive unit to keep everything in place.
Hold the trip odometer reset shaft with a pair of needle nose pliers while pushing the knob back to avoid breaking the reset mechanism.
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