I'll start with the most important information first... 2010 GMC Sierra, 94k miles. 4 weeks ago was driving truck when urgent beeping came on and said "oil pressure low" and "shut off engine." I did just that, I pulled over shut off engine for a minute. (Mind you it was -17 degrees). When I started it back up no lights or alarms, pressure gauge read about 40, started driving again, no unusual noises from the engine. Oil pressure starts visibly dropping till alarm starts going off, warning lights, and engine light. Pulled over, checked oil, it was full. Oil pressure gauge would drop to 0. Turned around and went straight home. Called dealer and we decided together to have it towed to make sure I wasn't stranded in below freezing temps and to save engine from any unnecessary damage.

Service guy guy couldn't really come up with a reason that it did that but said they drained the oil and found metal in the oil.

So here is the whole story... We bought this truck used TWO months ago. 2 weeks after owning it took it in to dealer because of flashing/dimming headlights. Service changed a belt or something, came home with same issue! Took it back in, it was there for a week with no contact from service until it was ready (I know, crappy service). We purchased an extended warranty, so I guess they thought it was okay to not keep us informed or have us authorize repair. They had replaced they alternator. 10 hours (literally, 10 HOURS) later, this oil pressure light and engine light problem occurred. Metal in the oil sounds like a big problem. Service guy said he really thinks it needs a new motor. My warranty company apparently disagrees. Oh and the vehicle was supposed to have a 120 day from the dealer. It'* still in the shop, over 4 weeks later. Today I called again to see what'* going on and was told they are gonna replace the oil pump because my warranty won't cover the motor.

Any body of any insight to any of this?

I think someone is avoiding the cost of an engine rebuild/replacement. If you can, have it towed to another dealer and get a second opinion. New oil pump isn't going to replace shaved metal from other parts of the engine. Unless they actually took the pan down and inspected all the bearings(unlikely)

You might want to read the fine print in your extended warranty. Sometimes they will exclude engine/trans replacement.

Sunnybry, let me guess, you have the 5.3 liter engine? If so you're probably one of the unfortunate people to be plagued by the post 2007 Active Fuel Management (AFM) 5.3 l issues, most of them relate to high oil consumption though, but your stated mileage is in the neighborhood where problems arise. As Mike has stated, a new oil pump is not going to fix your motor and replacement is more than likely your only fix.

After a few phone calls, emails, and stress, our extended warranty along with the 120 day warranty and $800 paid by the dealer are gonna pay to put in a new engine! So glad I didn't just accept the stupid replace the oil pump crap! Shocked that the dealer made it happen, but very happy. Thanks for the input guys!

oil pressure readings should be taken at the oil filter and at the sender to see where the pressure is dropping off. it could be as simple as the valve lifter oil manifold filter is plugged. this filter sits under the eop sensor. is the engine making abnormal noise? you said you shut the engine off for a few minutes and eop on restart was about 40? if that is at idle on a warm engine with no abnormal engine noise I would first check the vlom filter and basics before condeming the engine. hope this is helpful