Hello. I was checking the transmission fluid level on my 2002 Catalina 310's Hurth HBW 50 transmission yesterday and noticed the sealing ring for the dipstick is missing and nowhere to be found. I understand this is critical to prevent transmission oil from coming out. The dipstick is listed in the parts catalog for this model transmission as a "dipstick/breather tube assembly". The only replacement I can find online is available from a European company for over $100. That is way more than I want to spend as the dipstick/breather tube I have is just fine, it just is missing the sealing ring. I wonder if I could order some rubber gasket material and cut a gasket just a bit wider radius than the dipstick hole itself. Then, when I thread the dipstick back in, the gasket should tighten down enough to seal the hole. Does this idea hold water? It seems ridiculous to spend $100 just to get a new dipstick because it would come with the sealing washer. Thanks for any advice!