I have a 99 SH with 80k miles. Since last week I have problem shifting into 3, 4 and 5. once in a while. The problem with 5 occurs more often. My clutch started to slip at the same time. Now after a few days my clutch problem seems to have died down. I also know that I've been running with more engine oil than i should have but I've have it for like 1800 miles. once i lowered my engine oil level the slipping of clutch ceased. Would that problem be happening because i have excess oil? but I've already had extra oil for so many miles. second, is that shifting problem means a bad pressure plate or if it is something else?