hello,
My speeometer moves up in speed to fast , it will sometimes bounce back to normal speed.
I thought i had it fixed when i pulled the VSS plug there was alot of tranny fluid inside the plug . Cleaned the plug and it was flawless for 4 days then back to erractic. I dont know if it was coincedence or if it is the plug. i checked the plastic gear at the tranny and it seemed fine as was the square cable to run the gear. Are there any test or troubleshooting i can do to trace the cause? Does the VSS either work right or not at all? or can it send erractic signals if bad? I searched and didnt see any details . thx for any help

 

The sensor could cause it, a loose wire, loose grounds, anything that could cause a voltage spike can mess with the speedo. My speedo went screwie for a while, found a loose ground on the alt field block. Look over all your wires, pos and grounds. Good luck

 

Thx Cat , i did a quick look at some of the wiring until i started to freeze to the ground .If it is a wire im suspecting the old trailer brake set up. ill get a better look tomorrow in the daylight.

 

What year is your truck? If you fill out the sig line on your profile with the model and year of your truck, we would know better if our experiences might work for you. Yours must be electronic based on what you cleaned. Did you have any fluid leaks that might have wet the connector?
Welcome to the site.
Nat

 

I did have a tranny leak, Thats all fixed ,
I noticed in the 4 days in a row the speedo was working the tranny shifted flawless. Im still trying to figure out whats involved in the tranny shifting , but if the VSS can send erractic signals to the PCM, then im guessing the tranny could shift erractic . All theory if im wrong im hoping someone knows .