My filter is a Hayward S-244T. If a multiport valve is the valve type with about 6 different settings, backwash, rinse, filter, closed, etc and rotates to each position, then that is what I have. I did not replace the gaskets because the valve was new when I moved into the house about 5 months ago, I did clean them and put fresh gasket sealer on them before re-assembly.
I just took apart the top of my filter again to inspect the gaskets (I could find 3 of them). They all look good, even the spider web looking gasket that fits under the valve handle and seperates the backwash/filter/rinse etc functions. I could see how if this gasket was messed up that it could cause the problems that I am seeing. But it looks great, is less then 6 months old, and I don't have any leaks that I can tell.