2. This seal is located at the extreme rear of the box, where the cardan shaft is connected to it. If a transmission fluid leak is detected, raise the vehicle and support it on vertical stands. If this seal leaks, oil will be found at the front end of the driveshaft. If the seal leaks significantly, oil may drip from the rear of the gearbox.
3. Remove the driveshaft (see chapter 8).
4. Using a special puller or screwdriver (see illustration), carefully pry the seal out of its socket located at the rear of the gearbox. Do not damage the splines of the secondary shaft of the gearbox.
6.4. Carefully pry and remove the existing oil seal from the extended part of the automatic transmission casing
5. Using a mandrel or a large diameter socket head, insert the seal into the socket, being careful not to allow it to become skewed. Make sure the seal is fully seated in the socket (see illustration).
6.5. Insert the new seal using a special mandrel or a deep socket head and a hammer
6. Lubricate the splines of the secondary shaft of the automatic transmission and the outer side of the driveshaft fork with grease, then install the driveshaft (see chapter 8). Do not allow the edge of the new seal to be damaged.
(The article is reprinted from the website: «ChevyMan»)