The Stovebolt Site Forums The Shop Area Engine Shop 1953 GMC Speedometer Question

In my 1953 GMC the speedometer worked when it was out of the truck, I installed it with a new speedometer cable and it doesn't work. I think it may be the gear in the transmission. Does anyone know how to check this or have a schematic that shows how to replace it?

Remove the cable from the trans. & put a small screwdriver in the square hole that the cable went in. If you put the rear axle on stands you can run the truck in gear & the screwdriver should go around. Or you can put it in neatral & block one wheel from turning & have someone turn the other rear wheel as you watch to see if the screwdriver turns. If it doesn,t you can remove the driven gear buy the large hex on the retainer or a bolt & clamp holding it in. I,m not shure which one this model uses. If the gear is bad you can replace it with one that has the same number of teeth. If the inner gear is bad you have to partially disasemble the trans.

If it's not moving at all, then see if the cable is turning by letting it hang under the dash and then looking at it while moving the truck or rear wheels. If the cable is moving and the speedo is not, that would be unusual.

I've seen many of the heads on the 47/53 speedos fry when the truck is run at highway speeds. It will make noise and then have one last gasp as the cable snaps because the bearing in the back of the speedo head is seized.

Scott's Speedometer in Pontiac, MI has tons NOS parts to repair, rebuild, and properly calibrate these and their work is first rate.

howdy Kook!

Bill

Did you check to see if the odometer is working? If it is, then you have a problem with the head. When the bearings in the head get worn, such that there is a lot of clearance in the thrust axis, inward pressure will cause the speedometer to freeze.