Yo,
This is from the www.
Issue was, "My speedometer needle bounces around, and it makes alot of noise when it
is cold; I think it is the cable. Does anyone know a trick to lubrication?
I haven't seen anything specifically for this purpose."
Speedometer cable lubrication
"take it off of the speedo head then remove it
from the T-case, try to turn it by hand just to see how free it moves, check for any kinks or smashed spots in the outer cable. for lubrication, remove the plastic gear and pull out the inner core from the top at the
speedo head. wipe the inner cable clean. if you have a compressor, blow air thru the outer cable to remove any debris. get some moly **** or a light wt. grease and put some on a rag. while you insert the inner cable into the case
slide it thru the grease on the rag turning it as you go, assemble and test drive that puppy !! JD
or you can do it the lazy way and just spray some **** down the cable at the
speedo head : ) "
Another reply;
"what I found on mine in the Tcase was a speedometer gear bevel wear situation.
The gear was so old that the point at which the T case plastic gear and the speedo gear come in contact with each other was worn so much it
didnt even make contact. I replaced the gear and cable and it works great 2 years later. Heat should not matter if both parts are in good shape. My 2c.........Mike Morgan"
Also,
The speedometer system includes a gear installed in the transfer case, a cable, and the gauge. If your gauge bounces a lot, try disconnected the cable from the back of the speedo and dripping some light oil or WD40 down the inside of the cable to loosen it up. Replacing the entire cable is sometimes necessary as these guys get pretty worn out and gunked up.
http://classicbroncos.com/tech/speedometer-rebuild-101
Our sponsor, Jeff has the cable;
http://shop.broncograveyard.com/Speedometer-Cable-66-77/productinfo/17130/
Removing speedometer head;
Disconnect the speedo cable, remove the 4 screws in the dash, then carefully push back and down to expose the wires. Disconnect wiring and pull the bulb sockets out to remove unit. Read more at
http://classicbroncos.com/forums/showthread.php?t=245915