The 1988 model, (like mine), was the last year they still used a speedometer cable. '89 and newer models used the Hall Effect three-wire speed sensor with no speedometer cable on the three-speed transmission, and two separate speed sensors with the four-speed transmission. If your four-speed is shifting fine, the speed sensors are working.
The first thing you need to observe is if the odometer is working. If it is, that limits the problem to the instrument cluster. If it is not, the problem could be in the Transmission Computer or the instrument cluster.
The next step is to use a scanner to see if the Transmission Computer is updating the current mileage, then see if the instrument cluster is updating.
Sunday, October 9th, 2016 AT 4:30 PM