123 Tranny

Ok guys I need to ask you the experts a question ok, Ive been adjusting my transmission so long I don't know. From great to good to bad. And that was just from changing the hoses by making it shorter to reach the traingle black rubber things to the the green shut off valve/ restrictor, not sure about the exact name. My grandfather is a mechanic but he doesn't know alot about Diesels. Well He has all kind of stuff in the garage so I did my own modifications. And when I did that the tranny did work pretty good but not the way I really wanted. But I let like that for months and just to live with it. Then I went to my benz mechanic that ive known since the day my uncle got his first benz. Well I saw him adjust something with a wrench, because I told him something was wrong with my tranny. He did it a couple of times and tranny was still jerky or even worse. So I was like forget about it, and thanks anyway. And I attempted to do it my self, its a nut on the right that moves the accelerator closer or something. It seems as I put it clockwise the shifts got alot softer and as I turned it counter clockwise the shifts were rough. Well I did it to a point, where the car now just shifts perfectly. I mean I put into gear with no delay or anything, just like a new car, and I can drive the car by pushing the pedal softly and nothing no kick or hard no kick, (No flares). Ok my big problem, I think to myself is this to good to be true?, will this adjustment I made ruin the tranny or something. Because the car not only shifts better it has alot more power. I dont have to floor it anymore. I was going to sell the car for a new car but after this near accident my mom almost had with the car, I feel this car is a keeper if it wasn't for the cars handling, weight and yes it's slow speed she wouldn't be with me right now. Im 20 years old and I can't wait to give this car to my son when he's 16 with a million miles.