1998 Isuzu Rodeo 2WD.My speedometer / odometer has quit working.

I suspect that the TCM is playing up but without a proper code reading it is difficult to say. Why do you not take it to autozone as they do scanning for nothing.

Are all fuses and relays ok? Also a loose ground wire can give u alot of trouble

You need to replace the speedometer gear that drives the sensor.

it could be the cluster but you have a im put and out put sensor on the transmission that controls the speedo

Usually it's the opposite. The speedometer works and the odomater and trip meter go inop. Most likely the speedometer assembly is bad. If the odometer is working you have a signal from the gray and black wire .

You need to replace the speedometer gear in the transmission. see http://www.myisuzuparts.com/index.php

You need to replace the speedometer gear. Its on the passenger side of transmission at the rear, not the magnetic sensor on top. That one is for the computer not the speedometer. Unscrew the sensor and unbolt the gear housing to get to it. I worked for an Isuzu dealer and have sold many of these gears. You can go to www.myisuzuparts.com section 2-25

Hi, I have a trooper also, I am pretty sure if it has a speed sensor it would ;located on the transmission near the tailshaft. Not sure that will help, but mine is a standard, so I can't look for you.
or the transfer case maybe?

You need to replace the speedometer gear that drives the sensor.

i think near rear of trans near output shaft