Ok I have the typical odometer problems on my 123 1983 300DT. The speedometer works but neither of the odometers work.

So i followed the tutorial Dieselgiant was kind enough to post. Here's the rub my odometers seems fine, all the gears look good, none of the cogs spins on their shafts. I then apply a close enough square driver bit to the cable opening, gingerly spin the works with a power bit driver, the odometer, speedometer and trip meter all turn as they should.

Ok so now I assume my cable is bad, but then why does the speedometer work when I drive? it is a little shaky below 20-mph but otherwise it works fine. Am I missing something?

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1972 280SE 4.5

If the speedo works then the cable is fine. The odo may work by hand but at higher speeds the torque on the gears is higher and can cause them to slip.

Ok seems logical. So this time I used an dremil tool extension cable which is very close to the speedo cable. I put one end in the back of the speedo, and the other in my Makita. Hell the makita will do 0-65 in under 2 seconds.

In any case the makita cruised at 65 mph for 5.3 miles, both odometers worked fine. So am i missing something?

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1972 280SE 4.5

it is possible that when you reassembled the odo, you fixed the problem inadvertently there are several gears that must turn for the odo to work, and you may have shifted them when you put it back together. I would check the plastic gear directly connected to the speedo cable, the next, and the next... the DG.com site is nice for fixing the hard gear but it fails to explain the rest of the gears that can fail on the 123 odo.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

My odometer fixed itself many times, but it never lasted long. Things usually seized up on the 9's...9.9, 19.9, etc. If you try, you can probably get that silver-grayish gear to spin on its shaft. Once it starts to spin, it'll slip more often. If you've got it all apart, you may as well poke the shaft out and rough-up the end, put it back in and do the lock-tite trick. Go easy with the locktite, I used a toothpick and almost glued the wrong thing the the shaft on the first odo I fixed.

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

Don't even bother with loctite or glue. Scar the shaft lengthwise where the gear sits and it will never slip again.

My shaft that runs through the odo gears would bind. I took it out and sanded it to debur it. This was because I "fixed" it, lasted 65.3 miles, "fixed" it again, for 57.6 miles. After sanding the shaft, it went over 150 before I sold the car. I found it by inserting a broken speedo cable and spinning slowly. I could see the white worm gear actually bending under the strain of trying to turn the gears. That's when I figured something was wrong. The gears should spin nice and easy, mine were difficult to turn.

I did this in addition to the loctite on the TD (and roughing up the shaft probably would have been enough, but I already had everything apart), but on the 240, the gear was so loose it still spun after I scratched up the shaft end. It probably spun for 50,000 miles.

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1985 300TD-euro 352,000 mi
1974 240D (1?)52,000 mi - has a new home now

I used red loctite on my 81 years ago and fixed the odo. The gear was slipping on the shaft. Also NEVER rotate the tripmeter back to zero while the car's in motion, that leads to the gears getting loose on the shaft

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81 300CD (sold) 1972 280 SEL 4.5 (sold) 1966 250 S 4 spd (sold) 1974 450 SL (sold) 86 BMW 325ES (sold), 1973 280C (sold) 1988 300 SE.