[isa540]

Hello,
I own late 1998 model [7/1998 is manufacturing date to be exact] PSD F 350 dually. I was checking turbo wastegate controller by hand and I noticed it is almost impossible to move. I thought I should be able to move it back and forth but it didn’t move at all. Is this normal? If not, what could be done to correct the issue? The truck runs fine, however turbo whistle is somehow less audible than it was before when you accelerate while driving at highway speeds.
Thanks in advance,
Isaac