Speedo needle major bounce

[CG]

So my speedo needle bounces from 0 to 100 back and forth when ever the truck is in motion. Is the most likely trouble a bad cable, or a bad speedometer head?

[LongBox]

Cable is the usual culprit. unscrew the cable, and withdraw the inner cable. Is it frayed? Need to replace the inner cable.

Perhaps lubing it will solve the problem, but your case sounds severe.

[CG]

Ok, thanks ... Ill pull it out and take a look at it. Its a weird problem in my eyes, didn't know if a cable would do such a thing. I have extra speedo, not sure if I have a cable laying around.

[Steeveedee]

The cable is springy, and when it binds it winds up, and then when it slips again, the needle goes up. Pull the cable all the way out, and clean it really well. Then, pull the other end off the trans and run some cleaner or WD-40 or something through it, and let it dry. The get speedo cable lube, and lube it, and squirt it down the casing as well. Put it back together, and you'll be good to go. If there are any kinks in the cable, just replace it.

[joeydurango]

We just talked about this on another thread yesterday...

Speedo bounce is worse in the cold (more friction as things firm up with lower temps). With winter here, I bet there are several members with speedos actin' funny. I'd recommend a thin grease, because a thick one in the cold isn't much help.

[pritch]

Yeah, mine works fine in the summer, but bounces like mad when it gets cold.

[CG]

This one has been bouncing since I got the truck, but I seldom drive any distance and almost never at freeway speeds so I never bothered with it. Today I had to go a bit on the freeway and it was bugging me not to know the speed, had people driving close like I was holding up the line. I downloaded a speedometer ap for the drive home.

[special-K]

You just have to get to know that truck better. Mine has no dash lights right now and I drive by feel and sound. When it first started getting dark early, I'd keep grabbing the flashlight to light up the speedo to check my speed, but it was always right where I wanted it.

Or you could fix it. I need to put another circuit board in mine. Sounds like the cable is dry. Does it make any sound? Might do that either way, since a dry cable is usually why they break...or fray. Time to pull it out and see what you have going on.

[CG]

Funny you should say that. I felt like I was going darn close to the speed limit. When I used the phone ap it looks like I was only a few miles an hour off with my best guess.

I just don't use it enough though to really get to know it as well as I should. Too easy to hop in the little Scion. Company car, company insures, and pays for all gas and maint, and I can use it 24/7

[special-K]

I'm not liking driving at night when I can't see the gauges...any of them. My circuit board fried, I got another, didn't matter all summer, now sucks. But, I think I drove t the last time till spring on Wed. I have all winter to fix it.

Good luck with your fix.

[57taskforce]

Originally Posted by CG

Funny you should say that. I felt like I was going darn close to the speed limit. When I used the phone ap it looks like I was only a few miles an hour off with my best guess.

I just don't use it enough though to really get to know it as well as I should. Too easy to hop in the little Scion. Company car, company insures, and pays for all gas and maint, and I can use it 24/7

I hear that. I spend all my miles lately in my company truck... my 98 k2500 used to be my daily till I got my current job. It's nice to be able to just use the company truck as I need/please and not have to worry about gas and the rest. I've driven the '98 a whopping two thousand miles in the last 2 years. The speedo in my K/20 bounces pretty bad here lately as well. I figured it was binding up but I haven't taken it apart to clean it and lube it yet.

[supercheyenne]

Originally Posted by CG

This one has been bouncing since I got the truck, but I seldom drive any distance and almost never at freeway speeds so I never bothered with it. Today I had to go a bit on the freeway and it was bugging me not to know the speed, had people driving close like I was holding up the line. I downloaded a speedometer ap for the drive home.

I just purchased a truck off ebay. Drove it from Knoxville TN to Wichita KS (this weekend brrr!). No dash lights and it had "the bounce". Somewhere near Paducah KY it made the worst noise for about 30 minutes (it was dark so I couldn't see what was happening) and then I heard the sound of something small falling in the dash. Turned out my needle had broken off. LOL

Did I mention the heater didn't work? Yeah I'm crazy.

Oh yeah, I also used a Speedo app on my phone. They can be handy.

[special-K]

No heat app, ey? Bummer

[supercheyenne]

Originally Posted by special-K

No heat app, ey? Bummer

LOL not yet. Maybe someday.

I was stopping at every Walmart in Tennessee getting layers of clothing.

Ended up with snow mobile pants (overalls) and insulated boots. I had packed a decent coat so I made one wise decision among many poor ones.

After I get some pictures uploaded I'll brag on my purchase. It's a 68 short bed nicely optioned 50th anniversary truck. The previous owner "restomodded" it in the early 90's so it's dated and painted blue.

['68OrangeSunshine]

I get the blurry needle on both of my trucks in varying degrees.
On the '67 Chevy C/10 Stepside [L6 292/SM465/3.73 on LT235/85/R16 tires] I have a speed correction gear inline between the end of the cable and before the 465. It reads good until about 60-65 MPH then gets jumpy, above 70 it's unreadable.
On the '71 GMC Jimmy K/1500 [V8 350/SM465/NP205/3.73 on 33x12.50x15 tires, I have no compensator. Speedo reads about 10% ''slow'' -- so 50 MPH true reads 45 indicated. In town, I can calculate my rate, [although usually I just leadfoot it and drive the indicated speed anyway unless I know there's cops around.] On the freeway, the speedo dances way over the true speed and back. 70-75 true will read as 60-85 indicated.
On road trips, I use the GPS and get a true groundspeed. I tape it to the radio delete plate and rest the base on the pulled-out ashtray. I only wish I had a GPS that read out the MPH in 1" numbers in flashing red in the upper left corner.