Sounds like the sender. Mine acted the same way when it failed. You can check it with an oil pressure gauge before you do any extra work but I'm leaning strongly towards it being the sender.

 

do you know if the sender is standard threads? if so the truck i'm restoreing for my daughter had a mechanical gauge i can temp in to check the pressure.

 

I believe so, but am not sure. You can rent a tester from Autozone or another parts store. You leave a deposit and get it all back when you return it. I actually purchased one from Harbor Freight. I got a Mopar sender from Amazon for about 25 bucks and been good ever since.

 

i spent today installing a mechanical gauge along with the factory. at cold start up it has 50 psi and after driving a couple miles it drops to just under 25psi. which is where the factory gauge was riding all day yesterday.i didn't change the sender yet only so i can see what the new gauge is at if the stock one drops to zero again.hoping to get to the bottom of this quick. i have 9 days before we leave so if i have to change the pump i can.

 

alright now i'm getting confused. my wife has been driving the durango everywhere she goes and has put a couple hundred miles on it so far. this morning it was 5 degrees out when she first started it she had no oil pressure at all. so she shut it off right away then restarted it a few minutes later and had pressure. got to the end of our driveway and it dropped to nothing again. so she parked it and took our which might have blown a head gasket and overheated but that another story. we have never had a oil pressure problem untill i changed the oil last weekend. in the past i've always just ran normal oil this time i used the high mileage synthetic blend and the cheap fliter that came in the oil change sale at advanced. should i be looking at the pump or the oil/filter causing this? we leave for florida in 7 days so i have to figure this out quick

thanks
jason

 

SO was that on the mechanical gauge or the dash? It's possible the extra detergents in the synthetic could have knocked some crud loose and it's blocking something.

 

You'll defiantly need a mechanical reading to verify, or, at least change the oil sending unit then drive it, if it still goes to zero, then your gonna have to pull the pan, unfortunately if your truck is 4wd you will need to take the front diff. housing (front axle) out to get the pan off..

 

the zero reading today was on both the dash and mechanical gauge. i just got home with a new pump, pick up tube,pan gasket, cap,roter and pcv valve. i guess i misunderstood step 5 about dropping the axle i thought it was saying the front driveshaft. i haven't crawled under it yet but s**t this is sounding like an even bigger job now but i guess i don't have a choice.
heres what the fsm i downloaded says

4WD
(1) Disconnect the negative cable from the battery.
(2) Remove engine oil dipstick.
(3) Raise vehicle.
(4) Drain engine oil.
(5) Remove front driving axle (Refer to 3 - DIFFERENTIAL
& DRIVELINE/FRONT AXLE - C205F
- REMOVAL).
(6) Remove both engine mount support brackets
(Refer to 9 - ENGINE/ENGINE MOUNTING/FRONT
MOUNT - REMOVAL).
(7) Remove transmission inspection cover.
(8) Remove oil pan and one-piece gasket.

 

ok as far as the front end can i just take the front driveshaft out then unbolt the 5 (looks like it should have been 6) that mount the front diff without pulling the cv shafts? it looks like that would give me a couple inches of clearance i think i'd also have the lift the engine. does it sound like this would work? also which engine mount bolts is the fsm talking about the ones going thru the rubber mount or the ones that actually attach the engine to the top of the rubber mount? if that makes sence

also does anyone know where the vin would be stamped on the engine? a few things just aren't adding up. we've owned it for about 7 years now. when we first got it i had to change a water pump and noticed that the belt routing diagram on the core support was for a 4.7. we chalked that up to the bolt in core support must have been change at some point. we have a z vin code which is the 360 but when i was just under there i noticed that the passenger side engine mount looks like it has either broken or been cut.
also the support bars from the sides of the block to trans are not there. after all the times i've been uder there i have never noticed this and now i'm wondering if the engine has been changed out to a 318

 

How were the mechanical gauge along with the sender connected at the same time? Mind shooting us a pic of the setup?