Just checking. If I were to disconnect my speedo cable at the gearbox drive end and run the car like that would any oil come out of the gearbox?

Yes you'll run out quickly, why?

I bought a new speedo cable and I think there has been a mistake as the packet was marked 'Peugot 406'. The cable is like a 2cv cable but longer, and the bit that goes into the back of the speedo is making the needle jump and a clicking sound.

I have tried everything, really I have, re-routing the cable, refitting it to the speedo several times in case it wasn't in right but in the end i have to admit defeat. I travel 400 miles tomorrow and didn't want to hear the clicking noise all the way. I will disconnect it from the speedo end instead?

Does it look like this? The length shouldn't matter. RHD cables are heaps longer without any problems. Maybe the speedometer is faulty or the speedo drive at the back of the gear box is loose? A worn out rear bearing can give the same symptom

Yes it looks like that but much longer. I've tried two speedometers and they both jerk but they didn't before so I'm sure it's the new cable. Do you know what I think it is? The squared end of the upper cable is slightly too small for the part inside the speedo, so when it goes into the back of the speedo it isn't turning it properly but instead turning and slipping. I don't have chance to buy a new cable before tomorrow.

Could be, what happened to the old cable?

The plastic securing nut to the speedo back snapped off, it was fragile - and probably 24 years old.
I will disconnect the cable from the speedo to prevent any further wear on the mechanism until I can replace the cable for a better one.

old-Nail,
most of the racers run without any speedo cable, often using something as sophisticated as a wine bottle cork to seal the cable exit on the gearbox.
The nylon housing and bolt must stay in place, just withdraw the cable...

ken

Thanks Viking/Ken.

I've just been outside actually and disconnected it behind the speedo as I noticed a wet mist of gearbox oil on the casing near the speedo drive. I think there's been a mistake somewhere with selling me this cable, I don't know if it's a wrong 'un, or just one that should be on another car so fits poorly at both ends.

We had a few recently, exactly the right length but smaller square section at the speedo back, I wonder if you had one of ours?