Hi all, speedometer in my truck is bouncing all over the place. Needle won't stay consistant anything over 35 miles an hour.
I've read over the stickys and a few of the recent threads, but is there a quick answer to this? Most people point to the vehicle speed sensor. Is there a way to check it?
I've already taken it out and turned it. Went down to napa and looked at a new one and it turned the same, but it could be broken inside.

Anyone?

 

Mine and my brothers have done the same thing...replaced the VSS and problem solved.

 

I've replace the speed sensor several times, replaced the wires, replaced the weather pack plug. Works for a little while and then starts bouncing again. I finally found a thread on here that said water can run down the wires and into the plug and cause it to bounce. I cleaned the plug and the vss with starting fluid and used liquid tape where the wires go into the plug and I haven't had a problem since. Steady as a rock.

 

I tried removing it and cleaning the contacts and in general check things over and cleaned the body. Reinstalled it and about fifteen miles later started bouncin again.

 

Serious.
Check that the square drive hasn't rounded off, they do over time..
Check your wiring harness for cracks/breaks..
Also check that it is staying threaded on tightly.. they can be over-tightened and crack above the threads, letting them vibrate loose which I would guess could cause a jumpy or erratic speedo problem

 

Hi serious
Keep us up to date on your speedo situation, because we want you to solve the problem.
There's lots of folks here who can help, so feel free to ask questions.

If you've found out what the problem was, please let us know what was going on. When a thread ends with a solution it, adds to the value of the forum.

 

Does your truck have a manual or auto tranny? If it's a manual - getrag - I might have a solution to your problem.

Bob

 

what the solution? just wondering i have had the problems for 6 years...it suck not having the right miles,...thank you

 

My latest go-round with the bouncing speedo turned out to be water getting into the VSS electrics as deking1970 mentioned. Mine crapped out in heavy rain, so I blew it out with BrakeKleen, filled the connector with vaseline and sealed the plug (where the two wires go thru) with silicone sealant. It's been perfect ever since, about six months this time.

 

My speedo was giving me problems a while back also. I cleaned the connection at the vss and used dielectric grease and it has been good ever since.

 

My speedo bounce was caused by the wiring harness that runs back to the tranny and transfer case. Replace it and has been goin good for about 1000 miles so far

 

I had bad wires from my PCM, and had to clean them up. I put two VSS on and still bouncing. Ran new wires to the crankshaft sensor and then that went out and my alternator. Put new alternator in and a new CSS and works now...well for now it works

 

Had this happen a couple of times with the getrag. Speedo was all over the place.