My 7040 came with a bad loading mech (someone fished a tape out and damaged the gears), bad pinch roller, and dead capstan motor - I replaced the loading mech and capstan motor from a used donor Sony SDT-7000 DDS drive.
For the pinch roller most any Sony DDS/DAT pinch roller will work - you can buy a new one from Paul at prodigital for about $30 shipped. Full Compass used to sell these as well.
The 7040 has well documented error codes as well - that can help you pinpoint the issue. Open the top and watch the tape load as well.