Speedometer AND odometer do not work - help

[Whitefirstgen]

Read a lot about the gears going bad and causing the odometer to not work. Found the replacement gears but got to thinking. Is it the gears in the speedo if they both dont work? Or is it some sensor or something? They both stopped working at the same time.

Thanks
Mike

 

[Bob Beauchaine]

Welcome aboard - good to have new blood - helps us to keep focus on the future. You need to fill in your your sig. it will help us to help you. There are differences between the auto transmission and the Getrag manual transmission speedo drives.

Bob

 

[Whitefirstgen]

Sorry i will do that.

92 350 4x4 reg cab. Original auto transmission. What else do you need to know?

 

[mweiman]

Check down on the tail shaft of the transfer case and make the sensor and adapter are still attached and tight to start with. I know mine will come loose on mine every so often.
Matt

 

[RWherley]

Try this if your truck has cruise control on it go out on the road and see if it still works, if cruise works then the most likely the servo motor the turns the speedo is bad if the cruise dosent work then it the speed sensor or wiring.

 

[Whitefirstgen]

Cruise does not work. Will check sensor tonight to see if it is loose.

If not loose any way to determine if sensor is bad

 

[RWherley]

I don't know how to test it, but when mine went bad the needle would jump all over the place with no pattern at all.

 

[Whitefirstgen]

Needle doesn't move at all.

 

[Whitefirstgen]

sensor is connected and appears to be tight. wires look to be in tact but can only see a foot or two. i also looked at the fusible links to see if any obvious issues - non found. any other thoughts?

mike

 

[Bob Beauchaine]

Have you checked to see if the gear that drives the VSS is good inside the transmission?

Bob

 

[DVolk]

I had one were it was rounded off and it silppided inside of the trans on the VSS side look at it real close

 

[Whitefirstgen]

i talked to the guy i bought truck from. he said the speedo would work then completely quit, then come back for a little bit and then quit - no bouncing of the needle at all. The speed sensor appears to be tight and it good shape. There is some oil around the area but doubt that would be it. i can take apart the VSS and see what gears look like inside (looks like it is a simple threaded connection)

What about the gears in the speedo itself? i know a lot of people lose the gear for the odometer and simple fix brings that back - some say that both gears go and then speedo/odometer go out.

 

[DVolk]

Mine looked good as well the square nipple was rounded off inside were it goes into the transmission . Is the truck lifted at all or have weird size of tires ? that will cause issues as well check for shorts in the wires as well

 

[RWherley]

if the gears in the speedo was broke the cruise would still work, the sender gear is metal and I don't think it would brake, but the drive gear on the transfer case main shaft is plastic you might want to check it.

 

[Whitefirstgen]

Ok i pulled the speed sensor and the adapter both ends looked good. The adapter spun and I could see it spin the other end. The VSS spun freely. PLUS based on your feedback i decided to NOT trust the guy i bought it from and took the truck out for test drive. He told me cruise did not work. BUT the cruise DID work!!!! Back to gears on speedo???

Sorry for confusion.

 

[RWherley]

Ill do some checking it could me broken gears or a burnt out drive motor, ill see if I can find a way for you to test it.

 

[Whitefirstgen]

ok thanks! I have the dash apart right now and may just try replacing gears unless i hear something different. Looks like they are around 50 bucks.

 

[RWherley]

If you have a volt meter just check the wiring in the cluster and make sure there are no shorts.

 

[Whitefirstgen]

Replaced gears (small gear was missing teeth) and now the odometer works. Speedo needle does not move. Hmmmmm one than one problem.....