Miro R

Hi all, just last night as I started driving down the road I realised that my 1990 300E (178k km) would not shift out of starting gear. I'm sure it starts in second gear because if I floor it and hit the kickdown switch it will downshift briefly and go back into second gear. Shifting the gear selector into 2 or 3 does nothing, no matter what I try it will not upshift. First thing I did was unplug the kickdown switch, no luck. Checked the Bowden cable, all seems fine. Fluid change was done about 20,000km ago. Took it to a shop today and removed the governor cap and spun the wheels and of course the governor is spinning so I'm assuming that the infamous plastic worm gear has not broken and caused this issue. I am lost here guys and could use a pointer in the right direction. Thanks guys looking forward to hear what you have to say