Speedo acting funny

[tanusfarms]

So I got my truck unstuck from the mud today and was able to drive it and test the speedo for the first time. I got it to about 15 mpg by my guestimate but as I was driving the sppedo seemed to continuosly jump from 0 mph to 20 mph rapidly. I know its a brand new cable in it but it is a used speedo. could I have a issue with my sppedo?

[fordman]

its probably dirty and needs to be cleaned up. that is usually a dry dirty cable. was it lubed up when you go tthe cable? try cleaning and lubing the speeometer itself.

[Hawkrod]

Yup, as noted, it is usually a dry cable that does that not the speedo. Did you lube the cable? Light grease is needed. Also, if the cable is not installed smoothly and has any sharp bends or kinks it will also do that. Hawkrod

[Aussie_1970]

Similar thing happened to me as well, it was the cable not being firmly screwed into the cluster - that is the threaded part of the cable was very loose at the rear of the cluster and the speedo jumped around at lower speeds

[tanusfarms]

When I bought it it had a little package of grease in the packaging. I did use it to lube the cable before putting it in. Is there a specific lube that anyone would recommend me using?

[70_F100]

Lubriplate 103.

Been using it for the last 40 years.

[71highboy]

When I bought it it had a little package of grease in the packaging. I did use it to lube the cable before putting it in. Is there a specific lube that anyone would recommend me using?

you have to lube the whole cable not just the ends

[Whateverman]

I've had this prob a few times (with a few different trucks)-you can get away with any type of grease when you lube the cable up,just pull the cable out thru the casing from the speedo end , wipe some grease on the cable and feed 'er back in,you may have to turn the cable to get it to seat back into the speedo drive gear

[tanusfarms]

when i lubed the cable origonally I did pull the cable out and lube the whole thing. i guess I'll just have to pull it and try again.

[Whateverman]

I've also had the plastic speedo drive gear fail before when my cable seized up (..in both an NP435 & a c-4 equipped truck..) ,didn't shatter just chewed all the teeth down to the point where they'd skip..easy to replace,hard to find the right tooth count when raiding the junkyard though

[tanusfarms]

So I finally got off of my duff and decided to look at the speedo cable again. I relubed it and now it is working great. Thanks for the help I would have never thought to relube it after I had done it the first time.