Another Heat Control Valve Question

So, I recently noticed a lot of exhaust leakage from around the heat control valve shaft on my 308. I looked in the service manual for info, but couldn't find any. Is there supposed to be some type of bushing between the valve shaft and the exhaust manifold to prevent or slow gas escape from around the shaft? There is considerable play noticeable if you wiggle the counterweight and you can even feel the exhaust rushing past the shaft. It sure seems like there should be something in there to tighten up the gap.