I replaced my rear main seal, oil pan gasket, oil pump, and did the oil (new filter too). Started my truck no oil pressure unless I hit the gas and bring yhe rpms up then it goes up to about 40, and then drops right back down. What could thia be?

 

Put a mechanical gauge on it, and see what oil pressure is REALLY doing. Good chance it's just a bad sender.

 

Okay truck also seems to be smoking a little and before I changed pump every thing was good pressure wise... and where would I hook the gauge up?

 

Also sounds like a decent amount of lifter noise...

 

Need to put a mechanical gauge on it.