Flex disc question for manual transmission
 

OK, so this is the flex disc that I removed from the 84' Euro 280CE with 5 speed transmission. (part# 1234110315) It is very different than the ones used in the diesel cars with automatic transmissions. So is the difference due to manual vs auto transmission, or gas vs diesel motors? I need to replace them as they were original, and are shot. Want to make sure I get the correct ones for the 5 speed transmission, now running a diesel motor.

You need to check the Factory Shop Manual very carefully...
AND the technical updates put out by Mercedes over the years..

as sometimes they use two different ' firmness ' factors on one vehicle... it is not particularly safe to just replace with the same part number... even if original to the car due to the possible updates by Mercedes over the years after feedback reached their dealerships....

All I can say is that this is one of the handful parts I would make sure are spot on and NOT Euro Junk. If the disc goes, you know of the possible horrible results to property and maybe personal safety which could happen.

So this brings up the question of what is everyone running for flex disc when they swap in a manual transmission for the auto? My guess is they use what they have or the same as what they had if replacing them. How many have had failures due to using the wrong ones? I guess I need to know what is used with the manual transmissions in the NA 300D, and then order that part#.

I used the same ones for a 300D, auto or manny. It was the same part from memory. I bought Lemforder brand and they were not priced out of this world. Actually, considering the part, it's importance, and the fact it is a maintenance item, it was priced OK.

^ that is what I bought as well.

When I look up a 300d 5 speed on the EPC it states to use part number 1074100215 for the flex disk.

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According to EPC, the same part number (1234110315) was used with manual transmission Diesel cars. So it's the transmission, not the engine that determines. It's listed as NLA, but it does show up if you search any of the dealers.

I recently bought #1264100215. Meant for turbo diesels but is the better/stronger type. it's the torque rating of the engines that makes the difference, not what type of transmission I believe

Edit: Now that's interesting, neither my 4 speed or 5 speed had #1234110315 on them! They both had 1234110015...previous owners had gotten the different ones I guess

danger
 

This is what can go wrong if the drive shaft mounting is left to go bad .

Vonsmog do a check on GERMAN STAR web site . In the centre click on Mercedes Benz Parts Cataloge Then put in your w123 on the left .. But all should be above on this site you need to know ..

This is a soft release disc, you notice it says "this side to drivetrain" meaning to driveshaft. Its on my W124 car and the only added feature is that you cannot feel the transmission downshift. For manual I believe you need a solid rear disc on both ends of the driveshaft.

It bears noting that when diesel engines, and the 5-cyl in particular, are paired with a manual trans by MB, an additional inertia dampener typically is also used in combination with the front flexdisc.

I don't know about the part number issue but if you get a Flex Disc that does not have round washers in all positions as the one in the picture.

There is a special instruction on them in the factory service manual. Something about making sure the Tubes that go through the Flex disk will turn freely inside of the Washers.

Don't forget to take a look at the drive shaft centering bushings to see if they are worn out of round inside.

The additional instruction for this disc in the FSM is for positioning this disc correctly - the writing faces the back of the car. the other part is about releasing this disc for repair/removal - they tell you to use a rod/mandrel to loosen the bosses off the flanges so you dont tear the dampers out by pulling it violently like you can do on a solid disc.