My speedo cable was making the buzzing/grinding/whatever sound that I'm sure you guys are all familiar with. I had the same issue in my 80 TA, 75 Firebird and 82 GMC pickup. So I bought a brand new one from Hawk's Motorsports.

I decided to keep the housing I just swap the cables themselves. Pulled the old one out, put the new one in, no problems, spins real easy. Even though the new one came lubed, I put some speedometer cable oil on it anyway.

But of course, life being the giant **** sandwich that it can be sometimes, the new cable was too long by a good inch, maybe 1.5 inches.

So I cut it shorter with tin snips, little by little, until I could stick it in there and secure the collar over it. I also used a grinding tip on a Dremel tool to smooth the end into a bullet shape like it originally was and get rid of any fraying.

The speedometer was still jumpy like it was before, but it was silent. Good enough for me. That lasted 1 day. The next day, the speedometer doesn't work anymore. Won't budge. I took a look at the transmission end of it and it seems that the cable now has a sort of "bevel" at the end of it. In other words, the diameter of the cable is smaller for the last 1/4 inch of it or so. Makes me wonder if it was "eaten" down by the tranny.

Any advice on how to proceed? I was thinking of covering the tip in solder to try and even it out, but I don't know if there's anything stopping the solder from being "eaten" as well. What do you think?

The ends of GM speedometer cables are swaged into a square cross section. By cutting off the end(s), you cut off the square section that's used to drive the cable.

GM used to supply universal cables (in an AC bag) with a crimp on square end (last time I used one, the end was a hot-glue on type); you trim the cable to length then crimp on the square drive end.

As it stands, you essentially have a useless cable.

I'd go to Autozone or similar store and check out the HELP! section. IIRC, I've seen either speed cable kits or speedo cable crimp on drive ends; can't really recall for sure

Trim up the cable you have and try using just the tip from the kit on your cable.

The plastic square tip is on the speedometer side. I didn't touch that end. On the tranny side, it definitely didn't have any type of tip on it, it was just sort of bullet shaped. And like I said, it worked for a day, so it can't be COMPLETELY useless.