okay so my spedomoter is 30 kmph off, and that is consistant. it shifts fine and everything. could this be the speed sensor? 2000 odge dakota 2wd 4.7l

 

30 km/h is quite off I agree.

If it were like 5-10 I would ask if you changed your tires or gears recently.

Are you getting any codes? I know that the sign of a bad speed sensor (the one on top of your rear diff) is when your speedo doesn't work at all till about 30 mph (45 km/h) and youll get the ABS and parking brake light.

You do have a second one located on your tranny too but hopefully someone else will be able to chime in here.

 

usually output sensor will cause a code and cause a limp mode( stuck in second gear) check engine light will be on

 

it has a check engine light but the code is for a misfire. it has bigger rims and tires but nothing so big to make it 30 km off. i also heard of those symptoms for a speed sensor but i dont understand what else it could be. like you mentioned the spedo doesnt even kick in until about 30km/ph.

 

Wait...

Are you saying it doesn't move until you hit 30 kph, or are you saying you're going 60 kph but it reads 30/90 kph?

If it doesn't kick in till a certain speed it is most likely your abs/speed sensor on top of your differential, but normally thats accompanied by an ABS and parking brake light.

It may also be your output speed sensor which is located on the driver side of transmission. Check both for rust and corrosion.

 

it does both. im driving slow down the road, and it sits at zero, then once i hit 30kmph (checked it with a gps) it starts as if i just started moving, ect ect. so once im going 60, it says 30, then 70 is actually 40 ect ect.