gear box failt 4.4

hello ive a 2002 range rover 4.4 lpg converted , recently when i put the car in D try to set off it revs up and slams in to dear causing a screech noise , also in reverse , and when i put my foot down the speed goes up and when its about to change gear it revs up hight and slams in to gear and screech again , then the fail safe mode comes on , ive changed the oil and filter in the gear box but still the same , also when car is in N their sounds like a loud rattle tinny noise coming frorm the geat box as some thing is lose please please help !! xx the car has done 170k miles

sounds like flex plate

is that part of the gear box and tourque ? x

Its fixed to the engine and and drives the torque converter. remove the cover plate, back of the engine at the bottom the plate has been known to break up

in the middle of removing the whole gear box as ive bought a recon one with tougue will keep posted