Ok, I got the LoopBack to work.
But, now I can not get it to work in Normal mode.
I have it running on (2) Stm32f103C8 chips.
I have a mcp2551 attached to each board, and the mcp2551 chips cross connected.
But I always get a Transmit Fail.
And, always I see Nothing coming out of the PB9 (using Remap1) on the Oscilliscope, while transmitting once per second.