so i've been battlin this for a few months now but it's gettin really bad, i'll try my 96 cherokee around and sometimes the speedometer needle will jump all over the gauge, it all started when i caught my O2 sensor (downstream) wires around my drive shaft, theres a little sensor on the transfer case that ill wiggle when it gets real bad and the problem seems to go away for a little bit. Is this sensor on the transfer case the speen sensor and would it fix my problem? all my over gauges are acting normal just by speedometer is goin nuts, i really noticed it doin it a lot tuesday when i went down a bumpy gravel road,

Thanks in advance,
Redwolf

 

You can see the Vehicle Speed Sensor (VSS) in the pic of the TC. And what the whole VSS looks like in the other pic.


It sounds like the wiring to it got damaged.

 

yup, the VSS on the transfer case is what i've been playin around with, how hard is it to change that out, will that fix my problem and will i mess anything up if i change it out?

Redwolf

 

The VSS and speedometer gear are separate parts that work hand in hand.

It the gear is stripped of a few teeth or VSS is defective you'll get a bouncy or inop speedometer.

1 bolt and you simply pull the VSS out of the hole.....BUT you should clean around ir with degreaser or brake Parts Cleaner first.

This will keep dirt from falling into the hole and it will allow you to see how the VSS is indexed for the gear that is currently installed.

You'll notice a few different numbers on the VSS. these he index points used for gears with a different tooth count.

Those are used to correct the speedometer when you change tire size, gears in the axles or both.