Long time reader first time posting but after my first big 4l80e rebuild in my turbo 5.3 4l80e swapped 91 ranger I'm now having some sudden line pressure issues, overview of the build was full high energy clutch kit, all new bushings, seals, rings etc, rollerized rear case washer, billet rollerized forward hub, billet input shaft, dual fed direct drum, all new solenoids, new harness, transgo accumulator springs, sonnax overrun clutch valve kit, variable pressure boost valve, line to lube valve, drilled pump seal drain back hole, new pump gears, and freakshow triple disc converter, now trans has run great with no issues for about 5 days now, went got the truck dynoed made good power for the setup all was well and some street driving temps haven't ever got over 180 using hygard fluid everything has been great until this morning I decided to drive it to work when at one point I came to a stop fairly quickly and while I was stopped the motor shuddered for a second like dropping a clutch almost sat for a couple more seconds before going and everything acted normal, as I got going I checked my pressure gauge I still had hooked up and line pressure was still normal, now get to leaving and after warming up enough I start driving and after I get a couple blocks away and I start to hear a whirring noise from the trans area that follows rpm take a look at line pressure after feeling a slower than normal shift and it's starting to drop below 100 while driving by the time I pull into a safe parking lot less than a block away I'm at maybe 10 psi, check for any obvious leak but none to be found fluid level is still full so after sitting for a few minutes I start it up line pressure seems for idle so I put it in reverse and I get normal reverse pressure and after I rev it past 1000 I start to get the whirring again and line pressure starts to fall back to zero, after towing it home to look more at it I have now fault codes for any solenoids and after letting it sit for for a minute I can start it and get line pressure for a few seconds but the it slowlys drops off, disconnecting the plug to make it get full line pressure I'll get 230 and it'll hold for maybe 5 seconds and start to drop off, any thoughts on what might be causing this issue since I haven't been able to find any info with symptoms the same as mine, I was thinking maybe some kind of flow restriction to the pump causing it to starve for fluid and cavitate, at this point I'm at a loss to what the issue this time is and I'm quite frankly sick of fighting with thing and am considering just getting another junkyard unit and sending it?
video of noisehttps://photos.app.goo.gl/MxPLH92KBTikrd6o7

 

-low on fluid
-filter fell out
-filter is plugged

for any of those 3 solutions, you need to drop the pan.
verify the dipstick reads correctly. I don't trust any of them anymore. Stock, expensive, cheap...doesn't matter...they all need to be marked.

if the filter fell out...install a new one with a new seal

if it is plugged...figure out why...and fix it

 

fluid level is full, I've verified off the pan surface and marked the dipstick accordingly, filter is brand new only has a few hundred miles on it, how common is it to see filters fall out

 

I agree with Maroon Monster.
Every vehicle that goes through my Shop will have the "Actual" Full-Mark added to the Dip-Stick; regardless of having Transmission service performed at the time.
They are almost all wrong... and it can become a stupid excuse for why something failed.

Below is an image of how I will add a notch to a Dip-Stick for the "Actual" Full-Mark:


The notch that I made is past the "Original" Full-Mark, to the right side of the image.

 

I did mark the stick for the actual full, filter was in place but given what I found in the pan I think the pump ate itself