Truck Repair: Rear Main Bearing Leak, Cummins BTA 5.9, cummins engine, pcv valve

Question
In a group that I belong to, dealing with Oshkosh Chassis Motorhomes one of the fellows inquired as follows. I thought to present this question to you and ask for your advise.The engine is mated to an Allison 6 speed automatic and the unit is a rear engine pusher type motorhome.
Thanks
Gerry

""The rear main bearing seal (transmission
end)is leaking on the BTA5.9 cummins engine. What caused it, is
there a PCV valve on this engine that could block causing the
crankcase to pressurize. Can the seal be replaced by dropping the
pan, removing the bearing cap driving the top half of the seal out
then driving the top half back in then replacing the bearing cap.
This is a very common method on other engines."
If this is not possible , what would be the correct method to replace the leaking seal.  

Answer
You will have to remove trans & flywheel.There is no PVC vale,only the "blow-by" tube on the right rear that is clamped to flywheel housing.The seal is a one piece unit.If the crankcase is pressurizing,which is unlikely unless some one plugged off the blowby pipe,Then that would need fixing to keep from doing this again.