The cause will most certainly be from up top in the Valley (many times this gets misdiagnosed as a Rear Crank Seal)
Here's an interesting video, BUT I have to warn you about this guy,,,, he makes
some Good Videos, that Does NOT make him infallible. He's got some really GOOFY theories (not about this though) So, don't take him as your Guru, as many do. Confirm his advice on anything else he says 😉
powerstrokehelp.com