I would second the suggestion of trying Recuva. It's a dumb name, but it's free, and has had very good results for me in recovering damaged partitions.
A 4tb drive can be running into a lot of issues, regardless, though. Certain controllers and NTFS block sizes can cause serious chaos. Make sure your controller and OS support partitions of the size you're working with.
Make sure you don't write anything to the original drive, and double and triple check your steps. There is a lot of peril there.
If you totally fail, there's always OnTrack. You'll have to send the drives to them. And they cost some money. But they're like dark magicians at data recovery. They can do unholy things.
