so, first off, i went to take a picture of the part i found so i could post it and see if anyone knew what it was, but my kids had already found it. they thought it was a toy, and ran off with it... so of course it's lost now. but i am looking for it. hopefully my description of the part will be enough to give y'all the idea.

i have an 87 f-250 with the 460/c6 setup that was in it from the factory. i was having issues when it was cold and i'd shift into reverse. i'd have to tap the gas to get the tranny to actually engage and begin moving the truck backwards. this didn't happen all the time though. the previous owner said he'd rarely even checked the fluid, so i figured it was probably low on atf and also likely in need of a new filter. i dropped the pan and found me a mystery piece sitting in the pan. here's where i hope i am descriptive enough

it resembled a top like the toy you'd spin, except that where you'd expect a point to be, there was what looks like the tip of a hollow point: there's a recess in the tip. end to end the piece is about 2 1/2 or 3" long. it's round and about 1" across. if you imagine a top, the end that would be against the table is rounded, not sharpy angled, and the entire base piece is probably only about an inch of the 2 1/2 to 3" of length. the rest of the piece looks like a dowel, but only about 1/4" in diameter. on the 1" round surface, there was a groove with what looked like a hard black plastic version of an o-ring. the main piece was made of a whitish plastic type material.

at first glance, it looked like some sort of pressure bypass, or something that would close off a passage until a certain pressure was met. it looked like the black o-ring would seal off a bore that this piece would fit into, and the rounded end would seal off a slightly smaller tube that it would press against. my guess would be that it maintained pressure via a spring mounted behind the piece.

most of the diagrams and schematics i can find on c6's show there being bypass valves and whatnot, but i can't ever tell where exactly they go in the transmission, and none appear as though they'd be this large. also, the ones i can see don't look like they could ever just fall into the pan, not without some structural failings that would lead to there being other debris in the pan, or at least a spring. i found nothing indicating part or structure failure. when the pan was down i grabbed a flashlight and looked around for somewhere where this piece came from but found nothing. i'm a bit preplexed as to how it even came to be in the pan while still intact and like-new in condition.

i'll try to sketch something up and at least post a pic of the sketch tomorrow.

 

Sounds like the plug they had in the dipstick tube hole in the factory. It gets pushed into the pan when they fit the dipstick tube and sits there until the first fluid change when it is discarded.
Looks like yours is the first fluid change from new.
Don`t forget to also drain the torque converter while you are at it.

 

here's a pic of the sketch. if you viewed this piece from the end, it be the shape of a circle, about 1" in diameter.

@lazy K. i dunno wether to be happy that it's not in internal part falling out of the tranny, or sick that i'm the first one to ever change it =/. odometer says 87K, but it's only 5 digits long and i would imagine it has rolled over, and i'm at least the 4th owner. originally this truck was a commercial fleet vehicle.

well, the fluid looked decent when i dumped it out. not burnt, but time for a change.

any other possibilities as to what this could be?

 

No its is exactly what Lazy K said it was.

 

okay! thanks for the help guys! it had me worried. i guess i've never been the first one to drop a tranny pan on any vehicle i've owned, as i've never seen or heard of it before.

much appreciated!