Help!!! Oil leak on a 07 Suburban

[Badburban]

I have a oil leak and at first i thought rear main seal because it was all in the bell housing. So i spend my Saturday changing the rear main. Well that didn't fix it. After putting it back together it didn't leak at first. I drove it down the road. Pulled back in the shop, left it running and noticed it was leaking. I also noticed that when the truck is holding good oil pressure"40 lbs at idle and 65 under acceleration" it is not leaking oil. Now the oil pressure will drop out to 18lbs at idle and 37 under acceleration, the truck starts to surge and the oil starts leaking. I looked at the pressure sensor on the back of the motor and didn't see any noticeable leak. All the oil appears to be in the bell housing!! After 12 hrs of rear main by myself.......I am lost! Any help would be greatly appreciated!!!

[Podor]

It could be the rear main housing or the cam sensor. The sensor top flange is near the top of the block by the oil pressure sensor, but it seals below. There is a gap between the bell housing flange and where the sensor seals, so the oil leaks into the bell housing area. Not sure about the oil pressure or surging issues. It could still be a sending unit, also causing pressure readings to be off or the screen underneath.