No doubt, the ugliest job of all on the 240. Dropped my automatic trans earlier this week to replace the rear main seal. I had been getting about a six inch oil stain under the car after every shutdown, right from the bellhousing grates. Old seal exploded into pieces when I pulled it out, so surely this was the problem. New seal was light colored, not gray, came from Groton. I was careful with the lip while installing and did not seat it all the way to the back so as to find a "new spot". Crank hub was polished with 600 grit and cleaned before the new seal went in. I put Permatex aviation sealer on the perimeter, tightened the seal housing bolts slightly as well as the pan bolts. Leak is very much diminished, but not gone. Top and back of engine are completely dry as is the top of the bellhousing. Spent an hour with the crankcase vent (again) this afternoon. At idle, the plastic oil cap will dance just a bit, but there is slight pressure, not vacuum that I can feel. Should there be? If I pull the intake tube hose and blow back through the flame trap I can feel air coming from the valve cover with the cap off without blowing very hard--can hear it clearly. Flame trap is clear as is the separator from what I can tell. Small vacuum line is new and clear, all hoses clear, strong vacuum signal to the flame trap. However it seems to me there should be stronger vacuum at the oil cap even at idle, no? And if that's not my problem, did I mess up the seal installation? Hard to imagine. Damaged seal housing perhaps? Any new input on a much discussed repair will be appreciated.

DS