The Stovebolt Site Forums The Shop Area General Truck Talk 1937 Chevy 1/2 ton pickup Speedometer problems

Hello I hope someone can help me out. I have a 1937 Chevy 1/2 ton pickup truck and my speedometer is not working, I unhooked the speedometer cable from the transmission . I hooked the shank to a cordless drill and ran it in slow speed reverse and the speedometer worked at the dash , Next I jacked the truck up and put two jack stands under the rear axle and then started the truck up and put it into gear , I then found that the small shaft that the other end of the speedometer cable hooks into at the transmission was not turning , I spun the shaft with my fingers while the truck was still in gear and it was turning a little bit but mostly slipping. I tried to tug the shaft out , I dont know if it comes out ,I did not get it to come out . Does anyone know how this assembly works? Does the shaft come out? Can I get a replacement? Any help is welcome Thanks

The speedo drive gear is a press slip fit on the front yoke of the universal joint. There is a driven gear (small one 90 degrees to torque tube) the speedo cable has a square end on both ends and just plugs (slides) into the driven gear. Looks like your cable just broke; you should be able to pull it out out of the driven gear end.

I just put mine togeather 2 days ago.There's a matching nut on the opposte side of the tailshaft where the speedo cable hooks to the tranny.If you undo that nut you'll see it seats the other end of the speedometer gearshaft.It should slide right out.It wont pull out from the drivers side.The gears are probably stripped.

I did not look on the other side of the tranny , but I will check it out and pull the assembly out , If the gears are junk can you buy the set up new? Or do I have to have a machine shop make them?

Thanks for the help
Mike

I never looked to see if you can buy them new,I'd check out ebay,one may show up there sooner or later.

I might have some speedo gears but you will also need to check the gear on the U joint too,when I put my 37 togather the speedo did not work with a good gear screwed in the trans and I found the gear on the U joint worn down proabaly caused by the other freezing up and not repaired in time. Jeff

Mike,here's a pic of the gear and the ends.The green cap is next to the end the speedometer cable screws on.You'll see that side has a shoulder that catches it from moving out the speedometer side.I also put the yoke that holds the u joint so you can see what the other gear looks like out in the open. speedo gear

Thanks for the help guys

I am interested in the speedo gear that slip out of the tranny , I pulled mine out today and the gears are pretty worn. I Dont know if its a project to check the gear inside the tranny.

thanks for the help once again!
Mike

Thanks for your help, I was wondering how much of a project it is to check the gear that runs the small shaft thats inside the tranny . I did not take anything apart except for the nut on the housing on the passenger side of the truck and pulled the shaft out and my teeth on that are pretty well shot. How do I check the gear that drive the small shaft?

All help is appreciated
Thanks
Mike

I'm not sure if you have enough room to peep into the hole and have someone turn a tire to inspect that gear.If not you'd probably have to drop the driveshaft and pull the yoke out to see the gear.