1992 e 300 3.0 Inline 6 .. Tranny slips out of top gear. It might go a couple of days with out doing it,or it could do it after a couple miles of driving. Sometimes if you gun the accelerator and let up quickly it will go in to top gear. It may stay in gear or sometimes the slightest movement of the accelerator it will downshift. The reason im hoping a bad valve cover gaskit is because the underside of the auto is covered in oil. The engine never smokes because the leak is in the back, but it soaked the tranny mount enough to soften it and require replacement. I cannot afford another tranny and hope its as simple as a Tranny flush. Help this poor boy driving a money pit.