I now how old are T series. I started in august 2008 on 2 T400.
On these old arrays disks replacement is done by support not by end customers as it is done on 7xx0.
Thanks for the education
I'm not in charge of support in my company but the few failed disks i paid attention to never had so many errors...
One thing you could do: insert old mag in your active array, do admithw, check if the disk are in a good state, remove the spare from them (removespare -f pdid:a) and dismiss the pd (dismisspd pdid). That way you will be sure the disks you use are valids.
For the trouble you are facing i got no idea.
You can ever try this :
showpd -i
controlport chmederr set -1 pdwwn
controlport chmederr set -2 pdwwn
controlport chmederr unset -2 pdwwn
controlport chmederr unset -1 pdwwn
controlport clearerr pdwwn
That will force the reset of some errors...
But... I did not know forums was made to replace failed disks.