Good Morning Everyone,

Working on a 72 Roadrunner with a 340 Auto. The speedometer needle starts bouncing all over the place at around 50 miles per hour, get worse the higher you go. Any ideas?

Thanks,
Jim

pull the inner cable out of the sheath up at the speedo end & lube it with some graphite lube from your parts house. dont get the lube real close to the speedo head, maybe up to the "collar"

Yes...


There is a graphite 'chain&sprocket' lube that works well if used sparingly...

Will give it a shot, hope it is that easy lol.

Thanks!!
Jim

You dont feel lucky! You might unhook the cable at the trans end & straighten it out & spin it with a drill & you may even need to take the speedo head out & spin it up with the inner cable (a short piece of one from a junk cable assy is even easier) to see if the issue is in the head (grab some helpers if using the long OE inner cable).

Yeah, it's weird. It is rock steady until I hit 50mph, then starts going crazy. Hopefully can figure it out this weekend.

You might even call a speedometer specialty shop run the symptom by em & see if they think it might be in the head or in the inner cable/sheath. If you do spin the cable use your reverseable drill & go CCW. I dont have the last word but it sounds more like a cable/sheath issue.

Hi Everyone,

Just to close this out, I replaced the speedometer cable and it is now solid as a rock all the way to 100

Thanks everyone for you input!

Jim