Greetings to all and HELP!

[broncoza]

Hi there from South Africa. I own amongst a few other cars a '96 S600 W140 which has 200k on the clock. Just finished doing the air cells and was driving the car every day when the gearbox played up. During the service I replaced the bush on the selector linkage and the box started by feeling as if it was not fully engaged. Then it refused to change gear at all. I can get D,R and P but the box refuses to shift either automatically or even when you move the lever into each gear. I had it at the local dealer and they say they found no error codes!!! But said I needed a new box. Can't really accept that since their quote could buy a small car. Can anyone give me some ideas? Computer,hydraulics,solenoid?

Rob