One of your BIG problem is fixing. If you put Tmax 400 in fix, you'll see at 45 second mark, the emulsion will START to clear. It takes about 2 to 2 1/2 minutes to completely clear. Rule of thumb is double that number. I do 6 minutes.
Fix it again for 5 minutes. Wash again, then photoflo.
By the way.... Tmax400 is an amazingly fine grained film. So much so that it's almost as good as traditional ASA100 film. You should be fine on grain department.