What is this part?
 

Shifter was getting jammed and wouldnt shift past reverse to get into neutral or drive... after pushing on it a little, this little part fell out under the car.

can somebody please tell me what it is?

it is a small round piece of what looks and feels like aluminum.. it has a crossed slot design in the top for pulling it on and off of the car

around the sides it has 2 0-rings

here is a crappy microsoft paint picture of it that i drew

thank you in advance

What engine (V6 or 4 cylinder) and year of car?

What is the diameter?

Check the sides of the trans for what may now be a hole the size of the plug?

Its about 1.5-2" in diameter

Based on the cover design and number of O'rings appears to be the cover for the 2nd gear coast brake assy.

Look for a hole on the side of the trans facing the radiator.

Suggest you don't drive the car as the cover holds in a piston and rod plus springs which may pop out.

The cover is held in by a large snap clip which must have come off.

thank you all for the help!

here is a picture of an actual transmission

in this pic you can see the piece in question

The is the cover as described in the previous post.

Behind the piece is a piston, looks like a round disk the same diameter as the hole. You should see a rod end protruding from the exposed side of the piston and a snap ring holding the rod onto the piston. Make sure the piston is still installed.

For the cover you will need to obtain a clip that looks much like item DHT at the link below. Might start with a Toyota dealer although this is a standard part if you can find someone that sells it.

The plug installs, then is pushed in. The hole has a groove around it. The clip is compressed by pulling the two open ends together with a hand tool to reduce its diameter then inserted into the hole/groove. Once the tool releases its grip the clip expands into the groove.

Rotor Clip Company - Retaining Ring Product Line