I just got done gettin my speedo working again(gear reducer box) and it worked good for a few days, now it bounces, even when I'm stopped

BTW I just did some sterio work on it

 

Mine did the same thing, the speedo sensor on the trans was bad. A new one fixed it.

 

Check the main body ground and the cluster ground.

 

Mine was doing the same thing. It turned out to be a oily plug at the VSS. It started doing it again a few months later. That time the speedo went dead after a couple days and it turned out to be the adapter. I had to order a new one. Problem fixed. It started doing it again not too long ago but this time I didn't know what to even check. The plug was clean and the adapter was good. Voltage at the plug was good. Turns out it was just poor connection on the male terminals on the plug going into the female end of the plug. It seems good for now but every once in a while at high rpm it will give a little bit of a twitch. I used copper base antiseize in the plug to help with the connection. It helps. I wonder how long before it will start bouncing again. Only time will tell. Right now I have a dead odometer. The little bugs that keep coming up in my truck are starting to drive me INSANE!

 

you're gonna have problems with just about every vehicle you own. for most of us, these trucks weren't taken care of very well until we got our hands on them. "a chain is only as strong as it's weakest link." when you fix one thing, another thing goes bad. typically in electrical. just the way things go sometimes. at least they're little bugs and not big ones.

 

x2
Happened twice, since I broke the plastic tab that holds it in place. DOH!

 

Whats the voltage at the pluck suposed to be?

I checked the main ground ,its good but I'll check the rest when I get back home

 

Mine's a Getrag but I had identical problems until I rotated the speedo output shaft journal about 10* counter-clockwise. The shaft is off-center in the journal to allow adjustment of contact between the worm drive on the tail shaft and the plastic gear on the speedo output shaft. Mine has a 1/2" cap screw holding it to the side of the transmission; I loosened the capscrew and wiggled the whole rig to make it turn the amount I needed. Wish I had the truck here so I could get a picture to show this. Let us know how it works out.

 

None. The VSS makes the voltage.

 

well the voltage at the plug going to the vss for my truck was about 4.7 or so. My speedo works perfect now and it still has about 4.7 volts at the plug with the key on.
I remember when I was trying to troubleshoot this on the other forum in the winter someone told me the plug was about 5volts. I seem to think it might have even been philip.

You could always attach a drill the the shaft coming out of the vss and see if you get a consistent reading.


Yes it was philip, there should be 5v going to the vss apparently. I found the thread over on the other forum. Post #7. (It's not my thread, it's just a link he gave me last winter to help me trouble shoot my problem)
http://www.cumminsforum.com/forum/89...questions.html

 

Manual trans trucks use a 2 wire VSS that has no voltage supplied.

 

I guess you learn something every day. I didn't know that wanna.

 

Got it fixed, It was just a bad connection at the plug and connector

Also put a good speedo in with a working ODO