my daughters 7 got stuck, fortunately at home, in gear.
The first mystery when removing the drain plug was that no oil came out. Examination of the underside of the car revealed no oil on propshaft or underbody( I have a pit). The painted garage floor shows no evidence of any oil leak.So remove the gear box. Examination of the outside of the gear box shows no oily marks , only road dirt, from our sand road.
Strip the 5 speed box and the mystery deepens everything is bone dry. Yes it had jammed first and second gear but there is no damage to any of the gears, bearings or synchro rings and nothing even has sign of any bluing however faint. The car was serviced 4 months ago and the box was filled with ATF using a long flexible tubed hand pumped filler. Each part of the box has been critically examined and show no signs of oil any where on the outside of the box. Even the outside of the rear oil seal is dry.
Now she had just driven 60 odd Km to my place and the gear box stick happened as she pulled up a slight rise into our yard. She had switched off and come inside and on returning to her 7 switched started the engine engaged first and nothing happened other than stalling.
So there is the mystery , where did the oil go and why no damage?
The drain plug is still in place or for that matter the level plug, not first time I have seen them fall out 
Surprised no damage though. 
