Grindhouse

Problems in Walmart….grinding sound on idle and when moving coming from the rear of the bell housing. My thoughts are input bearing on gearbox. A big job to take it out involving stripping the entire box. So its either Gearbox or Clutch which are almost knackered. We can move but should we ? Looking for help from the helpful Land Rover community and some mechanics.If its the clutch we have the parts. If its the gearbox its gonna get expensive….Try to keep this updated but its the last thing on my mind.Was it the gearbox oil I put in not one week ago !