ive had some pretty big oil leaks for awhile and once in a while when i got a little low on oil the check gauges light would come on when going into reverse.. i always attributed it to losing oil (i added 4 qts in 1500 miles due to the damn intake manifold gasket and a leaking oil pan gasket)
but that was fixed a few weeks ago and it did it again... and after i parked the car and shut it off, i checked the oil and its in the crossmarks in the normal operating range on the dipstick...

so im not low on oil, but what would cause the gauge to read low oil pressure while in reverse? if i put it in neutrol and rev the motor a little bit it goes away..

 

maybe your oil pickup tube fell off. hit the bottom of the oil pan with your fist. listen if anything bounces around inside the pan when you hit it. you could also check the oil level sensor connection. its that big bolt on the side of the oil pan

 

It's possible that the oil pressure sending unit is bad, or your oil pressure is really that low. Good sign is it's only doing it in reverse, so maybe just the sending unit. They are set to go on around 3-5psi. Best thing would be to put a gauge on and check for sure. Problem with that is it's a pain in the butt even if you have a gauge in your hand.

Sometimes the sending units leak from where the connector attatches to the unit. I've heard of oil being pushed all the way through the wire harness inside the car.

If it's not that, it's probably more serious... Get another sending unit and try it.

 

the sending unit was replaced when the transmission was rebuilt about 6 months ago, and the oil pickup tube (the plastic thing?) i think was replaced when we had the oil pan off a few weeks ago to do the oil pan gasket.. which by the way, this random check gauges light thing was happening before the intake manifold gasket/oil pan gasket/valve cover gaskets were changed

I think the oil level sending unit was also replaced when the trans was rebuilt 6 months ago as well

maybe the oil sensor for the gauge is defective or something? i dont remember ever having this problem before the tranny was rebuilt

 

Only way to be sure is to get an oil pressure gauge hooked up and see. Otherwise, I still think another oil pressure sending unit is a reasonable guess.

 

i tried an autozone oil sender unit and now every time i let off the gas practically the oil pressure goes to 0 (if under 10mph or so) so now i gotta take that POS out and put the old one back in which was fine 99% of the time as long as the air temp was below 80 or so

i'm pretty sure i have oil pressure because if i didnt, i think i would have blown my motor months ago, lol...i dont hear ticking so i know there is oil getting to the engine.. has anyone else had issues with these damn electronic OSUs?

 

No problem with a NAPA one.

 

You really need to check the oil pressure with a mechanical gauge. It doesn't take much oil pressure to prevent bearing failure ("blow the motor"). GM is satisfied with 6psi at idle on the LT1 engines. But low pressure is not going to be good for the engine in the long run.