I have an 83 sea arrow with a mercruiser 5.0. The outdrive says 898 on it. Upon filling the outdrive with gear oil, it slowly drips out of the back of it where the top and bottom pieces meet. It appears to be leaking from where the shift lever is. I have never seen or noticed this before, and am at a standstill with it. Has anyone ever experienced this before? Causes? Your help is greatly appreciated.