Another problem. Will I ever win?

[GNVAIR]

I was driving my GN last Sunday and had just turned a corner when I noticed the speedometer needle went to 0 and didnt come back up. I continued to my house which was about 2 miles away.I noted that the odometer stopped as well and the mph on the Scanmaster read 0.
Once home, I crawled under the car and unscrewed the speedo cable and tried to turn the inside. It was seized.
I stopped at the local Pep Boys on Monday and picked up a new Motormite brand cable. I got a 1 piece job to replace the original 2 piecer. Today, I installed the new one (what a project!)
When I removed the original one, I noticed that the end that goes to the tranny was twisted up and thus no speedo function.
I tested the speedo while I had it out and it operated smoothly.
Upon test driving, it still didnt work. I crawled under again and unscrewed the cable. I the reinstalled it and test drove. It worked, but now the speedometer needle bounceds excessively.
I tried the cruise tonight and it surged badly.
What I am thinking is either the new cable is too tight and needs to be lubed OR that I stripped teeth on the driven gear. What do you guys think?

 

[MeanBuicks]

Why not simply pull the driven gear out for inspection? Just one 10mm bolt.

 

[GNVAIR]

I just came in from checking everything out and the speedo bounce is worse than it was before
I first crawled under the car and pulled the gear out of the trans. The teeth look a little concave. I put it back in and slipped a small screw driver in the square drive hole. It felt tight and didnt seem to slip. I then took the dash apart again and pulled the center portion of the cable out. I lubricated it with synthetic grease and reinstalled it. I reassembled everything and took it out for a drive.At approx 35 mph, the needle bounced off of the 85mph mark. The cruise control in now useless. I am at a loss. What would cause the end on my original cable to twist up and now the speedo needle to bounce. I dont want to keep throwing parts at it. Maybe I should just buy another GM cable?

 

[Alky V6]

Are you sure there isn't a problem with the speedometer head?

 

[Intercooler]

Did you use lube on it? It was suggested to me that I use lock lube. This comes in an aerosol can and is basically graphite based. I used this in my R&R and it fixed my jumpy needle. Got to use lube!

 

[GNVAIR]

I used very light weight synthetic grease as I have with all my other cars in the past. I have no idea why this one would have to be different.

 

[Sleeper]

Lee
I had a similar problem. It ended up being a slight kink in the cable because of the way I had to route the cable. I ended up making a cable, cutting the sheath to length and re attaching the ends to avoid the kink, and put in a universal cable insert, cut to fit. And I lubed that sucker with a ton of graphite.

HTH
Paul