FWIW I love the way my original transmission works in my 81 300 D. First, it starts in first. I know it is not supposed to but it does. I just get it going in first and let my foot off of the throttle - I get an up shift to second. It will stay in second until I lift my foot off of the throttle again. I decide when to up shift: second to third, third to fourth. It’s great because it’s like having a manual transmission. With the transmission like this the car is very quick and fun to drive! If I need to scoot I just give it more throttle and she moves quite quickly, up shifting only when I want it to. I don’t know if other MB diesel owner’s cars drive like this but my mechanic says that’s how the transmission should work. I don’t know if that’s true but I sure like it.