The Stovebolt Site Forums The Shop Area General Truck Talk Speedometer in my 1952 3100 quit working

Hi All,
Once again I'm in need of advice. Last week on our annual color tour the speedometer in our '52 3100 with 235 and SM420 (4 speed) quit working. Going along fine when noticed erratic movement of speedometer needle followed by it dropping to zero and staying there. First suspected the cable, removed it and lubed it carefully. reattached it to speedometer and hand turned cable counter clockwise. Needle moved up to 20 to 30 mph with hand twisting the end of cable. Also removed speedometer gear from transmission to inspect. Teeth and movement seemed fine. Put a bright light toward threaded hole that speedometer gear came out of. From the limited view it appears the transmission speedometer gear looks good also. Reattached and drove. No movement of the speedometer needle. Will probably take speedometer out and have it rebuilt and purchase a new cable. Cable is about 20 years old. Also was wondering if I could lift rear wheels off the ground and turn them to see if speedometer gears were meshing and turning cable. The transmission was professionally rebuilt about 10 years ago and operates fine. As for many issues in the past any experiences and suggestions will be helpful and appreciated.
Dan (Chuck 52)

From your description the failure has to be at the transmission end.
The plastic gear maybe being pushed passed the internal gear in the trany Or barely engaging.
If you can spin the cable end and get a MPH at the needle.

Hi Chuck52, I would carefully inspect the square end of the cable and the square hole in the transmission gear to make sure they fit snug, could be one or the other is worn to the point of not spinning the cable, also make sure that the cable nuts are snugged down all the way, that is what holds the cable ends in the speedo head and transmission gear. Color near Alpena was very close to peak last week, I probably won't have a chance to go back north until all the leaves are down.

Also check to see if the cable has broken off at the square end where it goes into the driven gear of the transmission. The piece will be stuck in the end of the gear. In the picture the gear on the right has a broken off piece of the cable stuck in it. The left gear doesn't. You can see the square slot for the cable if you zoom in on the picture.

Jeff

Thank you,Jeff.
Good advice will check it out. Won't be able to check until April, but will get back to you after checking further.
Dan

Thanks to all Stovebolters.
Dan (Chuck '52)

Hello and Thanks to Guitplayer, 78Buckshot and Crummy,
Hoorah! Speedometer now working. Checked trans. speedo. gear by looking into trans. hole and turning rear wheel, Checked speedo. gear on side of trans., Checked speedo. cable by hand turning counter clockwise, lubed cable. All checked out fine (I thought). Still when reassembled did not work. Rechecked everything again. Closer inspectio, revealed the end of speedo. inner cable slightly worn near end (see photo). Replaced speedometer cable, re-assemble, test drove, works great!
Chuck 52

Dan - Thanks for coming back and sharing your info and results! Glad to hear its resolved and the info may help others who run into this problem in the future.

Bolters helping Bolters - gotta love it!

I can recall when I first got my 58, the speedo would bounce and act erratic.
I changed the cable with a slightly longer cable. For 2 reasons. Fix the bouncing needle and
if the cluster had to be pulled ,I`d have to disconnect the speedo from the transmission the cable was so short.
I wonder , if the cable angle to the trany causes that wear on the cable end?

Just make sure the cable is lubricated inside the sleeve to avoid future problems. When I bought a new cable, I removed the cable from the sleeve and coated it lightly with white lithium grease and re-installed it.

My Dad always used powdered graphite lubricant, because it never turns sticky like grease, it can't really oxidize. I think I still have a tube of it that I retrieved from the house where I grew up, when I cleaned it out after he passed.