OK,
The old half blind guy finally located the sender location.... HAHA!
Ordered new sender:
Yr 2000 3.9L Magnum eng
API Oil Pressure Sender
Part Number: 1843-07785828 @ Parts Geek $16.00

Ordered the proper socket :
Lisle 13250 Oil Pressure switch Socket Amazon ($13.00)

and a week later... give or take,@ 0700 hrs (Military time) I proceded to remove the old sender.
Not too much room to work in between the firewall, Distributor, and Intake.
at least with my "ST. Bernard" paws.

had a bit of trouble getting the red safety clip out, and broke off the sender from the metal mount. As you can see in the photo below, it is only attached with a 1/32" thick ring of the case


It, like the coolant temp sensor, was as brittle as Aunt Emma's ancient crystal vase, and snapped off at the junction, with very little exerted force But that was a Plus, as it facilitated the easier removal of the red clip, using a pair of needle nose to assist. (P.S. the red clip must come all the way out.)
I then had to use a screwdriver between the plug, and the sender, alternately on both sides, to free the plug.
Hey , It's been untouched, as far as I know, for the last 24 years!

With that taken care of, I proceeded to affix the socket to the remaining piece using an 8" extension on the 3/8" drive, ratchet handle. Easy Peasy, Eh??
Try as I might, I couldn't turn it. Not wanting to get fresh blood all over the engine should I perhaps slip.... and open a vein, treated with blood thinners,
I got a piece of pipe to add some leverage to the handle. The 3 ft pipe did the trick, to break it loose, (not off Thank You!) after maneuvering it around the air cleaner mounting bolt! And I unscrewed the piece.
It seemed to take forever to unscrew, due to the fine threads, and the
difficult location.
Well now came the really hard part.

Trying many times, I could not screw the new sender in place by hand.
If I got the correct angle I couldn't turn it, and if I maneuvered to be able to turn it, I couldn't find the angle to insert it! After a half hour of effort It began to get over 85 degrees, which is my outdoor exposure limit, I had to retreat to the coolness of my dry 77 degree home.
So Here I sit............................................... .............
I have to recruit someone with smaller hands to start the threads.
(SIGH!)

 

I was working on a mustang once, the variety that had the plastic timing gears.... The original gear had disintegrated, which wasn't a surprise, and fell down into the oil pan. Not wanting to have to lift the motor, and drop the pan, I tried to stick my hand in there.... Nope. Not happening..... The babysitter though, was a tiny little slip of a girl, with very small hands.... A bribe was in order.... So, I offered her 20 bucks to reach in there, and pull out as much as she could. She looked at me like I had grown another head, but hey, 20 bucks is 20 bucks, right? (this was back in the early 80's.....) She was able to clean out just about all of it.... there might have been some small shards left, that came out when I changed the oil. I thanked her profusely, gladly handed over the 20, and finished the job. The owner drove the car for another ten years.

 

It's now 1930 hrs, temps finally broke thru the 100 deg mark.
I got my neighbors 13 year old son, to come over. He likes working with machinery, and had the sender installed hand tight, in 2 minutes.
finished tightening it up and re-assemblng the air filter
He too got a monetary reward! ...and didn't even get his hands dirty.
Oil pressure now at a steady 40-50 on the dash gauge at idle of 1.2k.

 

I can't wait to be racing in Lufkin in September <sarcasm> Not that it's much better here in Fort Worth! And yea, it's a pain how much of the engine is shoved under the cowl. Be glad you don't have a 4th gen camaro/firebird. Half the engine might as well be in the cabin. I just went through re-sealing my oil pressor sensor and gauge tee, and replacing the o-ring and gasket on the distributor housing. So little fun!

 

I just did my sender a few months back. Looks like the same one you've got. Used Mopar and it failed quickly. Had to return and get another from the seller, so I hope your Lisle lasts. I used a 27mm impact socket for mine and it made the job easy. I set the impact gun on high and hammered away for a good five minutes. Just kidding....I used a step down adapter on a 3/8 wrench and was very careful not to break that thing off.

 

Makes you want to get out the 5# sledge and start beating the firewall!
Last engine I really worked on, was back in 2006...when I was 61, & still able to stand up without getting dizzy after lying on my back under the car.
I did an engine change, on an '83 Jaguar XJ6.



I pulled and junked, the Jag 6 cyl, and tranny, fabricated 2 new motor mounts, and tail-stock mount, and placed a rebuilt 1970 Corvette 350, with a set of Summit Headers, mated to a 700R4,
with a B&M ratchet shifter and used a modified 1 piece Chevy driveshaft, to get the power to the wheels. (The Jag, used a 2 pc driveshaft.) Had to use the sledge to get the tranny to fit...
I've forgotten the details now but did that in about 6 months after work, and weekends, and as finances allowed, most of that time was setting up the workplace, in a friends driveway. (with the ugh! H.O.A. Karen's overseeing)
And cleaning up after, not to mention searching for tools I just used.... LOL!!
Paint was a metallic blue- to metallic forest green flip flop. Sweet!

Now, I find I have to rely on others....when I need stuff done!