lost drive to auto box

Hello,

W463 SWB M103 petrol 3.0 litre  Automatic 3 door SWB,1992  reg XET 1 (no A/C fittted)

Engine oil pressure when hot  0.5 to 1 bar in D in trafic

running temp 80 rising to 90 in traffic

Have been using my glanden everyday for the last two years covers over 10,000 miles on average per year,

mileage at 163k (20K mine) its a 2 owner and I have had body restored and changed lots of old parts out a couple of years ago

Drives very well but a little slow compared to later models -of course :)  a nought to 60 in... er ......who cares !

Beeen using to drive from central london to Excell  last 3 days low speeds (that all you do do in London now!) Parked up in the parking

everything all as per nornal use.

Got in the G yesterday evening at the end of the day -started the engine all running perfectly well, went to select 'D'

  and nothing happened -it was as if it was in N ? when you put back into P makes a 'clicking ' sound ?

 autobox historty ,Never raced or driven mad ,box has Never slipped , auto box oil changed last year  and the filter -all been running very well ,and oil  is clear does not smell?

would there be a linkage that has come off /or something simple like that ?

Any ideas? 

thank you 

Mike AKA Tyrekicker 

Selector has a little play -but i have assumed old age ?