they don't want to spent the time trying to find the problem. In aviation maint. I have too, thats my training and experience.
just the same with my rear end, kept taking it in and and could not tell me what wrong with my rear, said it was normal. Well, it really got bad and told me it was my pinion bearing that was bad causing my pinion seal to keep leaking after the 4th time. I called Nissan USA and complained, told them this is BS!!!! so Nissan step up and replaced my rear and I had 98K out of warranty.