There is a very high probability that through the life of an E30 the odometer gears will go out. If your odometer gears are original and are still functioning as they should then consider yourself lucky. If you plan to own your E30 for the distant future then it will be worth bookmarking this page!
The process is fairly simple, the only tools you really need are a few small screw drivers.
Some people remove the steering wheel to remove the cluster but I found this to be an unnecessary step. After removing the cluster I tilted it on its face and slid it towards the passenger side of the car.
Step 1: Remove the underpanel
Step 3: The nuts you just removed hold on this piece, after the nuts have been removed, push on the studs from behind that those nuts were screwed onto (you do not have to look for it just feel around for a stud), this will push the trim piece out enough for you to grab it from the front and pull it the rest of the way off:
Step 6: Undo these two screws to undo the “ears” of the cluster, from here on forth BE CAREFUL to not over bend or bump the ears off stuff, if one of them brakes off you will not be able to securely fasten the cluster back up:
Step 7: Remove all the cables by pulling up on the middle plastic pieces (I used a screw driver to pry them up), once the black clips are up (they do not come off completely) grab and pull up on the connector. There is a yellow, white, and blue connector, there are two lightbulbs you also have to remove, they are connected to their respective connectors. There is one connected to the white plug and one connected to the blue plug. The bulbs just pull up and out also.
Step 8: On many E30’s there are also two smaller connectors that connect to this green piece at the bottom of the back of the speedometer, on my e30 there were two small connectors, they plug into the left side of the cluster, as the second picture illustrates all three connecting points go to the same point, so in theory it does not matter which of the three slots you use when you reconnect:
Step 11: Undo the 4 screws on the back of the speedometer. Do not try to take the speedometer out just yet. Take this green connector out first by pushing on the two tabs on both sides and pulling down and out:
Before putting on your new gears make sure you remove this brass piece, you do NOT need it with your new gears, it is deleted completely. To remove it take wire cutter pliers and pinch the brash pushing all over the place under it loosens up enough that you can pull it off. Do not try to force it off with pliers or anything of that sort. Just keep distorting it until you can pull it off with your hands:
After you reassemble the gears make sure to put the spacer on, and make sure to put it on the right shaft, as you can see I put it on the WRONG shaft (I put the spacer on the correct shaft before reassembly but did not take a picture) and have indicated the correct shaft:
Reassembly is reverse. There are a few options for where to get gears, I used garagistic gears; they are cheap and great quality.
Before ordering from anywhere make sure you know if your cluster is a motometer or a VDO, and order accordingly, if you have a motometer ignore the above link and use this:
How to tell what you have: