I would argue that the biggest example of redemption in this brilliant novel is when Johnny dies. You may think this is a rather strange example to focus on, but if we think about what he writes in his final letter to Ponyboy, we can see that Johnny's death is redemptive in many different ways. Let us consider what he writes for one moment:
Listen, I don't mind dying now. it's worth it. It's worth saving those kids. Their lives are worth more than mine, they have more to live for. Some of their parents came by to thank me and I know it was worth it.
Not only was Johnny's sacrifice redemptive in the way that he was able to save children whilst hurting himself, but in a sense, Johnny was able to save himself through his act. Note his transformation from a greaser, an outcast of society who is thought of as being a rebellious and useless individual, to somebody who is thanked by parents and a hero.
In addition, let us also focus on the way in which Johnny's death is redemptive in terms of the impact that it has on Ponyboy. Let us remember what Johnny says to Ponyboy specifically:
And don't be so bugged over being a greaser. You still have a lot of time to make yourself be what you want. There's still lots of good in the world.
It is this final message from Johnny that encourages and inspires Ponyboy to look at his life in a different way and to try and put it down on paper to help others. Johnny's death is therefore a key redemptive moment when we think about how he manages to save so many people, including himself, through his actions.