Speedo Bouncing under 20MPH

[Dutch Rutter]

New yet annoying issue. The Speedo needle has started a bounce, I only see it at lower speeds, and only when just starting to drive the truck for the first 10 minutes or so. When slowing to a stop, the needle falls not a smoothly then bounces back up a few MPH. then when It should be zero it bounces up to 40 then falls back down to zero.

I've also noticed a faint metallic "tinging" at low speed. Kind of like a sprung spring or metallic teeth slipping. Could be unrelated I really have not idea.

Where should I start looking into this? Gauge, cable, T-case, or cable adapter for tire size.

FYI, just moved into the new house so tools are still buried in other packed things.

 

[idahovette]

I'd bet on the cable being a little "dry"??

 

[Vbb199]

No grease in cable, or you have damage/breaks on the cable housing preventing it from rotating smoothly.

(Ask me how i know)

 

[Dutch Rutter]

Thanks guys! I'm assuming the easiest way to inspect and lube the thing would be taking out the gauge cluster? and lube top down.

While the easiest way to twist the cable freely would be from underneath?

 

[idahovette]

Try it from under the dash, you may have enough room to push the holder and disconnect so you don't have to take the cluster out. Like Vince says before you take the cable out check for any kinks in the outer sheath from the case up. Good luck!!!

 

[DoubleDingo]

If you have the cruise control, it will be much easier to lube the two cables going to and from the transducer.

 

[Matt69olds]

I have seen homemade grease adapters made from a old speedo housing and a grease zerk. Then you could disconnect the cable from the transmission and lube it that way.

The issue with injecting grease at the transmission end is there is no way to get the old crud out of the casing. Not to mention typical chassis grease is entirely too thick to use on a speedo cable.


The best method is to remove the gauge cluster. Disconnect the cable from the transmission. Pull the cable from the cable casing. Spray a bunch of brake clean down the cable casing to flush the grease and crud out of the casing. Wipe the cable clean, apply fresh lube, reinstall the cable, reassemble. Good luck.

 

[1987 GMC Jimmy]

Cable. It needs to be graphite lubricated, and you can use denatured alcohol to suspend the powder. I disconnect it at both ends and work it with a drill from the bottom while I pour from the top. Honestly, the grease would be a better lubricant in the short term, but you’d have to do it routinely and pump out the old and dirty. The graphite offers less lubricious in my mind, but you don’t have to worry about it unless it starts bouncing and grinding again. It tends to do that with the onset of colder weather.

 

[jake wells]

Type 00 is what i use for speedometer cables it is neither solid or liquid grease and it works the best though it is pricey and messy.

 

[ali_c20]

Never had a non bouncing needle. Doesn't bother me as I don't really care about how fast I'm going.

 

[Itali83]

I’ve always liked the little bounce of the needle. Makes me know it’s mechanical and has age and mileage on it. Gives it character. I like when they go backwards in reverse too lol.

Ben

 

[59840Surfer]

Any needle bouncing is actually the drive cable is stopping and restarting every revolution. It means there's maybe individual wires in the cable that have broken or the whole housing is dry.

I don't like taking the cable end of the back of the speedo - but it IS do-able if you're dedicated and have girl-y small hands.

The alcohol-graphite is the best lube - but there are some commercially available lubricants that go in wet and dry to a nice slippery dust that lubricates it very well.

In days of old, we used CV joint grease - which is moly-based and it is extremely thin as far as greases go.