The Stovebolt Site Forums The Shop Area Engine Shop Speedometer

I have a 39 GMC, and I believe it has a Chevy 4 speed transmission. I bought a new speeodometer cable w/housing for a GMC. The cable has square ends and fits in the speeodometer fine.

It doesn't turn. I removed the part on the transmission the cable housing screws to. It appears there may be some sort of adapter missing to turn the cable.

Now my question.. Could the Chevrolet have a different style cable?

Is there some type of adapter missing?

Maybe some one can lend some insight on this issue. I tried looking in the parts book, but can't seem to identify anything other than the seedo gear.

Thank you, Jim

Jim:

I have the same tranny (albeit a touch newer) and have the same problem -- but with a stock cable.

I'm pretty sure that the nylon gear on my drive unit is shot. Have you checked for movement on the drive unit? Another way is to pull the yoke and the rear seal and inspect the drive unit for damage.

Chev. & GMC should be the same. If you screw the part in the trans. out there should be a shaft with a gear on the end. That gear meshes with a gear in the trans. on the output shaft like Brendan say,s. Raise the rear wheels & put a small screwdriver in the hole where the cable goes in. Turn the driveshaft & the screwdriver should turn.

Thanks for the INFO.

I ensured the speedometer was working with an electric drill, it does.

I removed the adapter on the transmission (with a one inch wrench). Spun the rear wheels and the part turns.

The part I saw turn looks like a 3/8" tube with a slot in it.

There must be something missing.

Dont know what it looks like or where to obtain one.

thanks, Jim

Can you post a picture? Someone may know what the part is if he can see what you're working with.