Dan,

i need to do the same, but I need to do it to replace the oil level sensor as it shows up with a error every time the car is started. I do not know your reason for changing the upper gasket, but i would replace the oil level sensor.

My 2002 E320 4Matic wagon has been pissing oil since i got it at a 100k miles. The M112 and M113 are known to piss-oil out of the rear seal than any other benz for the same mileage. I think you should replace the rear seal too and lower pan gasket...

My 2002 wagon has now 186k I'm going to do everything at one shot. Rebuild the transmission my self(I have done these many times-they are very easy to rebuild). Rear seal with a revised bracket. Upper and lower pan gasket. Replace the stupid annoying level sensor which is between the block and the upper pan...

For the moment the car is fine and is driven everyday, but it pisses oil out of the rear seal, and the level sensor is messaging an error every time the car is started...

I'd do everything minus the transmission. Later this year i plan to do it as right now I'm working on other Mercedes transmissions...

Martin