The following part 683-0251 without the idler pulleys is NLA from MTD. Use Toro 112-0525. Now it won't be red but it is power black 0637.
I know a few of us still have the MTD auto drive that uses this bracket.
Edit: Add photo of the Toro part. Notice the different mounting style changes. It is simple to make the change over by using the appropriate parts.