PeachParts Mercedes-Benz Forum - Speedo options after swapping diff in 1981 300TD

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Did the electronic speedos also have an attachment for a speedo cable? Or was either/or?

The reason I ask is that the speedo I currently have has a cable attachment and cable running to it. Like I said, this car doesn't have the original engine or transmission, so if it has a speedo cable installed then maybe a PO swapped it out and I'm looking at a broken cable issue?

I'll take a look at the tailshaft of my transmission tonight.

Electronic speedos have no attachment for a cable. That's why they are electronic.

Old thread, but I still do not have my speedo working. As a reminder:

* my car is an 81 300TD
* the engine is a newer turbo OM617 installed by a PO
* It's possible the transmission is not original as well.
* whatever engine/transmission combo that is installed has a tach sensor at the bell housing (which I rigged the tach to run off of).

Several years ago I swapped the diff for a 2.88. The original diff had a sensor in it for the ABS.

Prior to swapping the diff the speedometer worked, afterwards it was no longer working.

The speedometer in the car (no idea if it is original) has a speedometer cable attached to it. I verified that the cable is not spinning when the car is moving.

This last weekend I changed the transmission fluid and took a few notes and pics of my transmission:

* it is a 722.315 model
* there appears to be speedo cable going into the the transmission (see pic below)
* there is a single black wire coming off the right hand rear side (see pic below)

Here are the pics:

1. I think this is the speedometer cable. I removed the 10mm bolt and tried to pull it out but it didn't budge. i didn't pull super hard for fear of breaking something:

https://bn3pap090files.storage.live....&cropmode=none

2. This is the black wire that is coming out of the tail. Not sure what this is for.

https://bn3pap090files.storage.live....&cropmode=none

Can someone verify that the pic 1 is a speeo cable? And what is the single wire coming of the tail in pic 2?

thanks

722.315 is a w123 transmission and yes that is a speedo cable in pic 1

Wire in pic 2 goes to the kickdown solenoid.

Thanks for the confirmation on the pics.

If I remove the 10mm head bolt in pic 1, should the cable pull right out? Or does it usually need some persuasion?

Quote:

Originally Posted by 240dddd (Post 4169603)

Thanks for the confirmation on the pics.

If I remove the 10mm head bolt in pic 1, should the cable pull right out? Or does it usually need some persuasion?

I just removed one today to replace a 4 spd, and yes, it should come right out. Worst case is you will have to pull it with pliers on the part that fits into the hole (not the cable!).