If the dipstick reads max fill (on level ground) on an engine that's at normal operating temperature and has just been shut off, it is overfull, guaranteed.

The dipstick is calibrated for a cold engine. If you check the oil when the engine's been run within the last 15 minutes or so, there's still quite a lot of oil in the top end, on the crankcase walls, and on the crankshaft itself (which is why racers who need every last fraction of a horsepower install windage trays). So just make it a point to always check the oil when the engine's been off for hours and you'll always be reading a true measurement.

Anywhere inside the safe zone on a cold engine is good enough, unless you're running at sustained high RPM (well above highway cruising RPM), doing off-road hill climbs, or racing, in which case you'll want to be as close to max fill (cold engine) as you can get without going over to keep the pickup from sucking air. And in those cases you'll be wanting a deep oil pan, an extended pickup, and a windage tray anyway.

My guess: You've got a flaky oil pressure sender. A failed oil filter would probably, though not certainly, have left you with an oscillating gauge despite the lower oil level.

 

Could a new rattling sound from under the truck be associated with the new trembling needle? It's a rattle from the front of the tranny/rear of oil pan area. It's not the cat. It gets loud then soft/gone then loud again.

I'm uploading some video/audio to Youtube of the noise source area and also of the trembling needle. I'll post to this thread as soon as it gets finished uploading.

What worries me is that two weeks ago I had my tranny serviced (fluid-filter-bands supposedly) and now this noise sounds like it's coming from the tranny. BUT... I didn't notice it until I started having the trembling needle problems so maybe the two are related. I also put Seafoam in the vacuum line & changed my oil within a week of that tranny service. Could I have a gummed up or failing oil pump?

I'm still hoping for the oil sending unit. Wouldn't that be the easiest to fix?

BTW, the oil level is at the full line with a dead cold engine now.

 

Here's the flaky gauge. It starts trembling at around :43 and jumps a bit at :55 or so.

http://www.youtube.com/watch?v=wSCLwnLDyUs


The vid of the rattling noise is coming soon.

 

http://www.youtube.com/watch?v=NKXyP29t5JU
(New uploads take a few minutes to process)

Listen to this rattle. The cat is tight and the guard/shield is tight. No rattling when it's thumped with a rubber mallet. The sound does really seem to be coming from the tranny area but I know sounds travel funny under a vehicle.

Could this be related to the oil gauge issue?

 

I would pull the inspection plate off the T/C area, and have a look in there for loose bolts, or possibly a broken flexplate. (dodge seems to want to call it a 'drive plate'...)

I doubt the two are related.

Oil pressure problem looks a lot like a flaky sending unit. Best test? Screw in a mechanical gauge, and see what it has to say.

 

Keeping in mind that while I am quick on the uptake, I'm really new at this truck mechanical thing... Where is the inspection plate & do I have to drain the trans fluid to open it?



I don't have a mechanical gauge. If I pull the sending unit and buy something to stick back in, it'll probably be a new sending unit. From what people here say, it's a bi+ch to get off so I probably only want to do it once.