Does anyone else have a fith gen with a really bouncy speedometer?? My bounces all over the freaking place and was wondering if anyone heard of this problem and possibly how to fix it. I had the problem before and the speedo cable broke. I replaced it and it still does the same thing. Could it be possible that it is the speedo gear in the tranny, I didn't change it when I swapped in the TH 350. Matter of fact it bounced so much that now the needle is stuck on the peg and now my odometer is the only thing that is registering. Kind of sucks when your speedometer is stuck on 85 mph and having to rely and remember what rpm is at what speed when your buddy is right next to you, pacing you telling you how fast you are going.
Thanx guys,
-Yoshi

Been in that boat already.... A new speedo gear and I replaced the cable. The gear was stripped some and the guy at the speedo shop told me that was what was causing it to bounce. hope yours is as easy to fix. :twisted:

hey thanx for the info. That will reduce my search and save me time from having to possibly tear the dash apart.
thanx-
-yoshi

one other thing you might want to replace or at least clean out the speedo cable tubing and make sure it is mounted with no kinks or sharp bends.... to do this one you will have to take the dash apart but it only takes a few min.

The Cruise Control is also a culprit. On the 76 I have I was having a lot of problems with that. I tried a new cable, new cable housing, replace the speedo and finally after being frustrated I bypassed the non working cruise control module. Stedy as a rock now. I will eventually replace the cruise control but not with the old mechanical Vaccume module. I'll go electronic.

Just a thought.

BTW;

The upper cable from my cruise control reached the Transmission fine so I just ended up unplugging it from the module and reconnecting it directly to the Trans gears. I trashed the lower cable.

HeHeHe... I am in that boat with my 79 right now I just got done with a 20 min ride through town ranging in speed from 20 to 65 and the whole time my speedo was jumping from 10mph to 80mph the only time it was reading right was when I was stopped at a light. I dont even have a tach so going by the rpms isnt an option. Not to worried cause the whole dash and gauges are being replaced along with the whole interior.

ga79elky

Wow, mine just started doing it this morning on the way home from work. Doesn't do it bad just about +/-5mph of what I'm doing, but I did notice a slight squeeking noise from inside the dash pod that started also and it sounds like it might be the cable.

If you have Cruise Control I'd bet money that is the problem and not the cable. The Cruise control box on the fender well is bad or binding inside and it will get worse over time. Tomorrow it could work fine it is just going bad.

That is my experience with those nasty little things. The Delco Amplifiers are around 50-75 rebuilt - if you can find one. There were thre different types, if I remember correctly. When I finally got rid of mine after trying everything else my speedo got solid with me again.

yah that happens on mine, seems to be more when its windy or im driving fast....it started after my cruise control broke, or at least the turn signal bar broke, and when we replaced it, we hooked it up wrong :( so i dunno

Dump the cruise control. it makes you lazy and less likely to pay attention. Just run a cable from the tranny to the back of ur speedo. I was having the same trouble and my needle eventually snapped so now i have a little stub for a speedometer. its kinda kool but it sux. The problem was the cruise control. one of the coils was broke and it caused the cable to wind up and then unspring shooting my speedo all over the place. finally cused my lower cable to snap and get all knarled up. Very messy. STRAIGHT CABLE IS THE WAY TO GO!!

ok, so this squeak is still related to the cable and/or the cruise control. did i get that right?

You know it could just be the gears going bad. I recall that mine was making some noise also. I know mine was from the module you could turn it by hand and it would make noise and I guess that it was transmitted through the cable to the speedo and then to my ears.

Some white lithinum (sp) grease on the cable should remove the squeek if it is just in the housing.

You could try lubricating the cables. A little tranny fluid works fine. If you have cruise control, you can do both from under the hood. It sounds to me, since the needle is stuck now, that somebody had the head apart and probably bent the needle. In the head, there's a small metal cup that has a magnet inside it. The cable actually spins the magnet and the magnet turns the cup which is attached to the speedometer needle. If someone had the head apart, it is possible that the little cup was bumped so that it is no longer exactly "centered" on the speedo needle shaft. When this happens, the magnet actually touches the cup as it spins and causes the needle to jump. This problem can also cause the squeek that you are hearing. It sounds to me like you are going to pull the head. Good luck.

I pulled the cable out of the sheath & put some moly lube on it. I reinstalled it & its work for a few years now.

When mine did it last year, it ended up bieng the speedo gear, that's the first place I would look.

August