Engine/Transmission (1994 - 1998) no speedometer

[JustScott]

Had three u-joints and rear brakes replaced. Now my speedometer doesn't work. Does anyone know where the speed signal comes from? My truck is a 98 12 valve 4X4 auto.

 

[Vaughn MacKenzie]

It comes from the rear axle if I'm not mistaken. I would check the wiring through there, and you might call the shop that worked on your rig.

 

[JustScott]

The shop wasn't real intrested in trying to help. The guy I talked to thought the signal came from the transmission, and they didn't touch the transmission. Of course they somehow managed to unhook my vacume lines to my front axle. I realized that about the time I buried my truck in some loose deep sand, when my 4wd wouldn't engage. So, I don't know how much help those guys will be.

 

[MPerez]

There is (probably) two sensors, one on the top of the differential and one at the output of the transmission. Either one can fail and the speedo will work, though it will seem to 'stick' until the trucks speed gets to about 10-15mph. Then it jumps up to normal. The wiring is probably unpluged or something simple like that. At least that's how the '98 RAM van I had to fix was working. Or not working... It had both sensors fail within a week of each other - and no speedo.