I have the same issue with my 345 on a 3k machine. I now suck up leaves with the deck up and then I lower the deck and go back over to suck up the smaller pieces. Where did you find the flap assembly at?
I've been through 3 impellers hitting hidden rocks and chuncks of wood along with normal wear in about 8 years of use. Here is what they look like after 2 or 3 mowing seasons.
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Being that Cub Cadet is such an awesome company that only makes throw away belt drive lawn mowers(for the most part) they no longer offer the replacement impeller.
I have not tried this one yet but I think it will work. Atta boy Deere!
https://www.amazon.com/John-Deere-Or.../dp/B00CSBQGMU
I decided to go out on a limb and make one myself. I have about 8-10 hours of run time on it and so far it works awesome. I cut the 1/4" pieces out with my plasma cutter and weighed each blade to try and keep it as balanced as possible. I then tack welded the blades for proper fit and spacing and then welded them in place. More welds were added after this pic. I did slow the impeller speed down because originally it was spinning it at about 4800rpm at full throttle. I installed a larger sheave on the driven shaft and it runs at around 2800 rpm now.
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I ran out of time this fall but I need to make a new housing out of steel. My old housing has plenty of duct tape on it to hold it together.
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