Passing the hearing test during your exit exam will not necessarily kill your claim. When I was discharged in 1970, I was only given the "whispered voice" test. Since then, the VA has determined the "whispered voice" test is not a reliable indicator of high frequency or noise induced hearing loss.
I applied for hearing loss and tinnitus in 2010, 40 years after I was discharged from the USMC. I wasn't sure if I would succeed with my claim or not because I had worked in civilian (federal and local) law enforcement for almost 30 years. I filed and received 10% for hearing loss and 10% for tinnitus.
The evidence I submitted included the following: IME/IMO from my private audiologist who had been giving me hearing tests since the mid 1970s, reports from my audiologist, spousal statement, my statement in support of claim, photos of me firing 105 howitzers in Vietnam without hearing protection, DD214 showing MOS as Field Artillery Batteryman, etc., 1986 receipt of purchase of "white noise" machine used to mask tinnitus, photo of white noise machine, etc.
I wish you luck with your claim.