Mopar Four Speed Transmission Rebuild - Four Gear Freshen

The first thing you'll want to do is to remove the side cover, so you can take a close look at everything inside and make sure your transmission is repairable. Check for broken teeth, worn shift forks, damaged engagement teeth, and so on. You can't see everything this way, but if you do find a damaged gear, you might want to get what you need before you start so the loose parts don't have to sit around.

One thing to take note of is the shift forks are not the same, so don't get them mixed up. The bottom one is for the 1-2-gear slider, and the top is for the 3-4. Check for excessive wear on the contact surfaces, but unless they have been abused, these rarely need to be replaced.

This is the order that you need to follow to remove the reverse detent ball. Unscrew the cap and then remove the spring. Then, using a magnet, pull out the ball. Finally, you can unscrew the tube. If you try to take the whole assembly out at once, you'll drop the detent ball into the case. Note the reverse light switch above.

Removing the input bearing retainer will uncover the snap ring that holds the input shaft in place. The input shaft and bearing can be pulled out the front, but often it's easier to tap it into the case and remove it with the main shaft.

The first step in removing the main shaft is to unbolt the tailhousing and rotate it to uncover the countershaft. The small key is supposed to keep the countershaft from rotating, but as you can see by the out of place key, this shaft has started to turn anyway. This could be an indication of bad bearings.