Problems with Ethernet driver 100Mb OK, Gb not OK

Hello,

Maybe someone's seen something like this and can shed some light on the 
problem.  This is a Power PC (83xx) using the Ethernet driver Freescale 
provides on the BSP ISO image.  100Mb works fine sending and receiving 
packets (lwIP is up and running well).  Gb initializes fine but won't send 
or receive packets.  The driver sends the packet without error, the jack and 
switch lights flicker, but nothing sees the data (Wire Shark on the PC is 
quiet)).  I tried direct connecting the PPC and PC and still get no packets 
received.  Switch back to 100Mb and all is fine.  It's not the hardware or 
cable because the flashed U-Boot will send Gb packets with tftpboot or ping 
and Wire Shark sees them fine.

What did I do wrong in my code that 100Mb works fine but Gb won't?  One 
difference I know of is U-Boot is built with GCC and I'm using Code Warrior 
to build my program.  I think it's a stretch to think that's it.  I could be 
initializing the non-Ethernet parts of the PPC differently than U-Boot, but 
could that leave 100Mb working and Gb not working?

Thank you,
Bill A.