Speedo noise in 71 911...

[speedo]

So I started to hear a whine from my dashboard while driving which increased with RPM. I thought it might be an errant seatbelt buzzer at first, but no. I pulled over and the sound went away. Started driving again and it gradually came back. I put my hand to the tach and then to the speedo, and the sound and vibration was definitely coming from the speedo....which still appeared to operate correctly. Drove another mile and parked it. When I pulled the speedo out of the dash and disconnected the cable, when I drove the car again the sound was gone. So the cable is the cause of the problem. Anybody heard of this?
I had already noticed a very minor swepco leak coming from the speedo elbow on the trannie and figured I would need to replace the O ring on the elbow. Now I am wondering if the two are related. How would a leak past the O ring affect the cable and/or performance of the speedo?

TIA

[Mr9146]

So I started to hear a whine from my dashboard while driving which increased with RPM. I thought it might be an errant seatbelt buzzer at first, but no. I pulled over and the sound went away. Started driving again and it gradually came back. I put my hand to the tach and then to the speedo, and the sound and vibration was definitely coming from the speedo....which still appeared to operate correctly. Drove another mile and parked it. When I pulled the speedo out of the dash and disconnected the cable, when I drove the car again the sound was gone. So the cable is the cause of the problem. Anybody heard of this?
I had already noticed a very minor swepco leak coming from the speedo elbow on the trannie and figured I would need to replace the O ring on the elbow. Now I am wondering if the two are related. How would a leak past the O ring affect the cable and/or performance of the speedo?

TIA

Sounds like you may be nearing angle drive failure. That, or your gauge is going to pot.

[grannysmith]

My cable would whine once I reached 30 mph+. I left the outer cable liner attached at the speedo pulled the inner out from the gearbox end. Re greased it and fed it back in, its now all quite on the western (germany) front.

Hth

[speedo]

I just lubed the end feeding into the speedo. As I need to replace the o ring on the angle drive anyway...while I am in there I will lube the gearbox end. Isn't the angle drive gear lubed by the trannie fluid, which is why a bad o ring will cause seepage? I can however lube the end of the cable at least.

Speedo