Be gald you do not have an extra Shim inside there. In my last "other brand sled", there was a shim floating around in the chaincase, from the factory. The oil got milkly and I changed it. Then it got milky again. I opened up the case and there was a shim lodged between the chain and the chain case. It was rubbed super thin. Also, there was a big chunk of the chain case gouged out near the seal. All the metal was making the lube milky.
Needless to say, the entire case and guts had to be replaced. However, it took the "other brand's manufacturer" 7 months to pony up and fix the thing. I heard every excuse in the book as to why my 2 year extended warantry did not cover it, even though it was still in effect. I think the dealer finally just fixed it. However, he did not replace the chain which was at the limit of the adjustement. I replaced the chain after I got it back.
Like I said, be glad you have nothing extra! Needless to say, that was my last "other brand Sled".