Mahindra bought the old Lenar factory, and changed the engine up a little in your model tractor.I don't know of anyone selling Lenar parts in the USA any more.I would get the engine serial and model number and start searching from there.I sell complete bolt in engines for the Jinma tractors and they are around $ 3K,but they will not fit your tractor
Check your couplings coming off the pump, uncouple and redo, its a long shot but we have seen it happen when one comes undone. But it would not cause that pressure drop.
We can get you that engine rebuild kit, if you need it give us a call.