Just went through that with Dads R boat. Had it at one shop twice and both times we were told that they could not find a leak and just topped off the fluid. Tried another shop and he could not find a leak in the “normal” places either but after a call to the company and replacing a check valve, the leak was found and subsequently repaired with new seals. Take BCBs word for it that there is a leak somewhere.Jim EbarbMany, LA (Toledo Bend Lake)2004 Cougar/ 225 OptimaxHumminbird Helix 12 Chirp SI on BalzOut Mount at bowLowrance HDS 7 at bowHumminbird Helix 12 Mega SI on Ram Mount at ConsoleLowrance HDS 8 in dash at console