If your transmission only needs a minor repair count your blessings. Major repairs can be quite expensive, so you are fortunate to come away with anything less.
Although a minor repair always sounds good, sometimes it’s not the best solution. For example if your transmission has a mechanically failing solenoid, simply replacing the solenoid should fix the problem.
Unfortunately it may not last long. The most likely reason the solenoid has failed is because of fine metal contaminants that are attracted to the solenoid due to their internal magnet. The armature begins to stick which causes shifting problems.
Those same contaminants are still attacking the other solenoids in your transmission as well as the new one you install. Without correcting the cause of the contaminants, you are only supplying a band-aid.