Speedo not working

[math]

Hello everyone, well my speedo stopped working.

The needle started bouncing a bit and then just quit.

I've replaced the speedo cable and still no luck

I also connected the cable and disconnected it from the back of the speedo to see if the wire inside of the sheath was spinning when i drive and nope, not spinning.

Took out the cable and tested with my hand that when i turn one end the other end turns as well, so the cables aren't broken within the sheath. I think it's inside of the transmission. I would love a helping hand on where to go from here please :'( I've never opened up a transmission before and it's scary haha.

Oh, i wanted to note that the transmission/gearbox is a manual 4 speed from a w123.

[Diesel911]

I have not done it myself but there should be threads on replacing the innards of the speedo.

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[Frank Reiner]

Originally Posted by math

Hello everyone, well my speedo stopped working.

The needle started bouncing a bit and then just quit.

I've replaced the speedo cable and still no luck

I also connected the cable and disconnected it from the back of the speedo to see if the wire inside of the sheath was spinning when i drive and nope, not spinning.

Took out the cable and tested with my hand that when i turn one end the other end turns as well, so the cables aren't broken within the sheath. I think it's inside of the transmission. I would love a helping hand on where to go from here please :'( I've never opened up a transmission before and it's scary haha.

Oh, i wanted to note that the transmission/gearbox is a manual 4 speed from a w123.

1) Remove the drive line from the back of the gearbox, including the flex disc.

2) Check the nut inside the three-legged yoke for tightness. There is a worm gear on the main shaft just forward of the yoke that drives the speedo gear. That worm is clamped between the yoke and reverse gear, and if the yoke nut loosens the worm will be free to slip on the main shaft, e' voila, no speedo drive.

[math]

Originally Posted by Frank Reiner

1) Remove the drive line from the back of the gearbox, including the flex disc.

2) Check the nut inside the three-legged yoke for tightness. There is a worm gear on the main shaft just forward of the yoke that drives the speedo gear. That worm is clamped between the yoke and reverse gear, and if the yoke nut loosens the worm will be free to slip on the main shaft, e' voila, no speedo drive.

thank you

I'll give that a shot tomorrow ( 3am in the morning here )

What can i do if it's completely loose and things have slipped off ?

Do i have to open up the gearbox or something ?

[math]

https://youtu.be/vYOgeHsEoWk

Here we go, i didn't see the yoke nut loose at all

but anyways, iot is fixed now, thank you for your help, much appreciated