The maximum number of hundreds is 3 and the minimum is 1, so that the thousands will be 9, 6 or 3.
The maximum ones is 4 and the minimum is 1, so the tens are 8, 6, 4 or 2. If all the digits are to be different, we could pick 3 and 1 for the thousands and hundreds and 4 and 2 for tens and ones: 3142.
If we take the thousands and hundreds we can have: 31, 62 and 93; and 21, 42, 63, 84 for tens and ones. That means we can have 12 numbers that meet the conditions:
3121, 3142, 3163, 3184, 6221, 6242, 6263, 6284, 9321, 9342, 9363, 9384. Of these:
3142, 3184, 6284, 9321, 9342, 9384 have no repeated digits. Take your pick!