Odometer failure
 

I have just reassembled the engine on my 1989 300SE after blowing the head gasket. All if fine and the engine is back to running smoothly. However, I noticed that the odometer is not working now. It had been working fine prior to the engine rebuild. Speedometer is working fine. I did some investigation on the forum and everything points to a gear issue. Before attaching that job of removing the cluster just to find out that it isn't a gear issue, what can I look at in terms of within the engine compartment where I had many things apart? I'm thinking it's a cable issue, but not sure. I just think that it is unlikely a gear in the cluster because it had been working fine.

Odd coincidence but it is probably gear related in the odometer. Sometime the number barrels slip on the shaft. Curiosity here...does the ODO work in reverse? The #'s should decrease.

Speedo wouldn't work if it was a cable issue.

No movement at all on the odometer. Speedometer works fine. Just wondering if I screwed up a cable or something because of the timing of the odometer malfunction.

In my opinion it is coincidental.

My issue (1990 300SE) with the odometer and tripmeter is that they run 3x as fast as they should, replaced the gears six months ago with new ones from eBay and it ran fine and correct. The problem started after an oil change and the new gears seems to be fine. Coincidence?

Not working at all I would think it's the gears, make sure to get the right ones for the m103. It's a fun little job, especially after doing a head gasket.

TY. I guess I will have to pull the cluster. I agree. After 4months under the hood, this job will be a piece of cake. Although, I still find it an odd coincidence of the timing of the failure. Keep thinking I did something wrong.

Be sure to count the teeth on the old gear. New one must match exactly or it will not work properly.

Just pulled and diagnosed. Two broken teeth! What a coincidence! TY for the help!

The plastic gets brittle as it ages. About the only thing we can do to reduce damage to the gears is to gently and completely reset the trip odometer only when the car is at a complete stop.

Ahh. I guess that's how I did it. I was resetting it after the long sit while I was rebuilding. Duly noted & thank you for the tip.

UPDATE: The three gears were replaced and all is working perfectly. I followed the directions provided by Pelican Parts and it was unbelievably easy and were written to exact specifications - if that is correct reference. However, the key here in ordering the correct gears is the second gear in the series. I only counted the inner tooth count on the first gear and the set arrived, but the second gear count was incorrect, so I had to order another set. Not a big deal. Only thing lost was about a weeks time.

it's an older post. Does anyone out of their head knows what odometer gears are needed for a 1990 W126 300SE? Most likely I replaced the original gears with the wrong gears, so I won't be able to use them as a reference. Thanks.

I had the same issue with my 1989 300SE. Best thing to to is call Pelican Parts directly. Speak only to the Mercedes expert. I spoke to him several times during my rebuild and he is very knowledgeable. He advised the correct set of gears and my Odometer works perfectly now. I would give you the part numbers that I ultimately received, but with these cars it's not certain that they will be the same. Best bet is to call. Takes a few minutes only, but well worth it.

Will do, thanks!