Introduction: Replacing Transmission Speed Sensors (Hyundai Trajet/sonata)

For those of you who have a Hyundai trajet or sonata that gives hell while driving on the highway, this instructable may help you out. The input and output speed sensors on this vehicle's transmission failed and the drive experience was really bad as in hard shifting plus the 4th gear refused to engage on the highway.

The replacement sensors were low cost and easily obtained from

Here is how I solved this problem.

Step 1: Removing the First Sensor.

First the electrical connector was unplugged then the 10mm bolt holding the sensor removed. The sensor came out easily after.

Step 2: Comparison Then Installing the New Sensor.

Here is new and old side by side. Installation was the reverse of removal, obviously.

Step 3: Accessing the Second Sensor.

In order to get to the next sensor, the transmission cable selector bracket has to removed. A 12mm bolt holds this bracket in place. Once the bracket is moved aside the sensor is accessible.

Step 4: Removing the Sensor and Dealing With Poor Qa Qc.

The entire sensor connector disintegrated. Thank you Hyundai for making the world's worst connectors!

Now I had to rebuild this stupid connector and complete the installation.

Step 5: Fixing the Busted Connector.

Using pieces of 1/8inch heat shrink tubing, I insulated the 3 metal connectors. I put them in the correct orientation and applied silicone adhesive for waterproofing.

Test driving the vehicle was a pleasure as the gears shifted properly and smoothly. Job a success!