My speedometer cable needs to be replaced in my76, It has stopped turning inside and the transmission gear is stripped. I'm not exactly sure how to do it, am I going to need to remove the dash to do it? Where can I find a replacement? I've already searched junkyards. Any help would be appreciated.

-AC

The dealer should have both the cable, and the gear. On the left side of the trans, you will see where the cable screws on, unscrew the cable, and then using a 7 1/16 wrench or socket, remove the adapter on the trans that the cable was screwed onto. Pull the adapter straight out. You will see the gear, remove it and take it to the dealer for match. You will only need to remove the hush panel below the steering column to remove the other end of the cable. Once you have the panel removed, reach up behind the speedo, and depress the spring clip retaining the cable to the speedo and pull straught back. If you have cruise control, you will actually have a two piece cable. If so, you will need to unscrew both ends from the servo, (drivers side, underhood.) (you may have only one of the two pieces broken or a frozen servo.

One trick I learned years ago was practice on another car. Grab some tools and head down to a pick-a-part junkyard. Try removing the trans gear off that car. Not a trans expert but on the 350 the cable and gear are the same. It is the gear that is mounted on the output shaft that changes the ratio. That normally doesn't go bad.
You should be able to at least learn how the things come apart and should be able to grab some parts while you are there. If you make an error, it's not your car. Just a thought.

Thanks for the input. I got a cable from the dealer and after getting it fed through and the old one pulled out I realized it was almost twice as long as my old one....grrrrrrr. I also learned that any person or manual that says you can just reach up under the dash and disconnect the cable is a liar :). I had to take the bezel and cluster apart to get in there, but it wasn't too hard. I test drove it with the new cable and the old gear and it worked fine, but the speedo was sitting on the passenger seat! Tomorrow I will get the right one and pick up the gear that they had to order. The one I have has a slight applecore wear to it so I will replace it even though it is working.

What can I use to fill holes in on the firewall? The hole for the cable is about 1.5" diameter and was previously plugged with some sort of rubbery goo. There are some other holes that need patching around there also, one was for a crazy trailer brake system that I got rid of awhile back.

-AC

I like to use duct filler. In the Navy we called it, "monkey ****".

It's a thick playdough type material that never hardens but is fireproof and waterproof.

You can find it at Lowe's or any electrical supply store. It is used to fill in holes when running conduit or wire through a firewall. I think heating and air guys use it for filling in holes.

I used it around my heater core connections.

go here:
http://www.usahardware.com/inet/webSession/store/dept-3/department/dept-3/item/30230/icn/20-543165/lookin/30230/g_b_electrical/ds-130.htm

Thanks, I'll take a look for that stuff.

I got into a small argument with the dealer, he insisted that the speedo cable he gave me was the right one, even though I brought it it and showed him that it was twice as long as my old one. He practically refused to find me a shorter one so I took it home and made it work. I had to loop it around the master cyl and the washer fluid resivoir and try to avoid bending it too much but at least it works now, and I can keep the cops off my tail a little longer.

It's an AC Delco part number 25032666 maybe some can figure out what the deal is.

-AC

Older Chevys used a rubber plug with a split in the center for the cable. My 72 Chevelle has one. Don't remember when they stopped using them but you might try that and look into that as an option. There's also a company I believe called Caplugs. They make plastic caps that insert into stamped chassis holes for commerical and avionics use. Might try a search on them and see if they will sample one to your "company".