Wandering Speedometer Needle at Highway Speeds
 

At speeds under about 40mph, my speedometer is stable, but it drifts around at higher speeds, as seen in this video:

https://youtu.be/5TxuNPqF8_g

I swapped in another speedometer I had, and it was even worse, but acted basically the same way. It seems like bumps in the road are causing the needle to move around. What can I do to fix this? Do I need to get a new/reproduction speedometer?

Re: Wandering Speedometer Needle at Highway Speeds
 

Try lubing the speedo cable. Doesn't cost any thing and it may help.

Re: Wandering Speedometer Needle at Highway Speeds
 

I did lube the speedo cable last night and it had no effect. It is a new cable, although the speedo acted the exact same way with the old cable.

Re: Wandering Speedometer Needle at Highway Speeds
 

Take the cable loose at the transmission and look at the plastic gear head it goes into. It's more than likely worn out. Take it out and buy the same gear put back in it. This is just example picture. Look into the end opisite of the gear that is where the cable goes. It should be nice and square like the cable and fit's pretty tight.:chevy:


https://cdn11.bigcommerce.com/s-6y2b...246081.JPG?c=2

Re: Wandering Speedometer Needle at Highway Speeds
 

Here's my gear. It's a 44-tooth out of a TH400. Looks pretty good to me, but I will replace it anyway

Re: Wandering Speedometer Needle at Highway Speeds
 

That gear looks OK. It could be the end of the cable that goes into the speedometer head also. Are the cable end going to the gear itself. How do they look?:chevy:

Re: Wandering Speedometer Needle at Highway Speeds
 

The cable ends look perfect to me. Here are some mediocre photos of them.

Re: Wandering Speedometer Needle at Highway Speeds
 

If he doesn't chime in PM TBONE1964. He will be able to talk to possible problems inside the speedometer itself.

Re: Wandering Speedometer Needle at Highway Speeds
 

Will do. Thank you. I did see a comment he made on another thread about a weak magnet in the speedo.

Re: Wandering Speedometer Needle at Highway Speeds
 

What did you lube the cable with?
Did you pull it apart and clean it inside plus the cable.

Re: Wandering Speedometer Needle at Highway Speeds
 

I used a Teflon based light grease that is designed for bicycle cables. I pulled the cable out of the housing, wiped it off, applied the grease and reinstalled. I didn't clean the housing.

Re: Wandering Speedometer Needle at Highway Speeds
 

I clean them out inside and the cable with acetone.
Then use white lithium grease for lube applied sparingly.
Make sure the cable is held in place along the lower firewall too.

Re: Wandering Speedometer Needle at Highway Speeds
 

I'll give it a good cleaning with solvent. I have it fastened to the firewall with the original clip.

Re: Wandering Speedometer Needle at Highway Speeds
 

Sheesh, mine always wanders like that and I never really thought anything of it. I guess I have another thing to fix.

Re: Wandering Speedometer Needle at Highway Speeds
 

That's what I'm wondering. Maybe this is common simply due to the age of our trucks. This is my fourth C10, and none of my previous trucks had this issue, but the last one I had was 13 years ago.

Re: Wandering Speedometer Needle at Highway Speeds
 

I have used graphite dust to lube the speedo cable, but the most reliable ground speed indicator is a GPS device on the dash.

Re: Wandering Speedometer Needle at Highway Speeds
 

I think cable issue is the most likely cause of a bouncing speedometer. I would remove the cable, pull the inner cable out of the sheath and a suitable lubricant (i.e. not lithium grease) such as:

https://www.amazon.com/Ags-Kable-Eas.../dp/B000ZO0EA2

Re: Wandering Speedometer Needle at Highway Speeds
 

I just put this new cable in and lubed the heck out of it, as did the OP, so I don't think it's the issue here

Re: Wandering Speedometer Needle at Highway Speeds
 

How the routing, do you have a sharp bend in the cable. Maybe disassemble the speedometer and lube the part of the cup/magnet part that the cable spins. Maybe it is binding due to hard grease at the housing.

Re: Wandering Speedometer Needle at Highway Speeds
 

The routing seems good to me, and there are no sharp bends. I already put a drop of light oil on the speedometer input shaft.

Re: Wandering Speedometer Needle at Highway Speeds
 

When I pulled my cable and housing out, Cleaned the inside of the housing and could not believe the grit and gunk that came out of it.
after a couple of good cleanings to the housing and cable, lubed with speedometer cable lube and good as new.

Re: Wandering Speedometer Needle at Highway Speeds
 

I have found those offset spedometer correction boxes [used when you have bigger than stock tires] tend to amplify the bounce.

Re: Wandering Speedometer Needle at Highway Speeds
 

I sent my speedometer to TBONE1964 and he ended up replacing the entire speedometer head with good used unit. The speedometer is drastically improved over my old unit. It is rock steady most of the time. It still swings around if I hit a bump or dip, but that seems unavoidable. Here's a video of it in action.

https://youtu.be/Cvvz8rQTz_E

Re: Wandering Speedometer Needle at Highway Speeds
 

My rig just rolled over 400,000.

Re: Wandering Speedometer Needle at Highway Speeds
 

Nice! That would explain your signature. I have no idea what the mileage is on mine. Probably less than that.