I think this came off something attached to the transmission? 1998 Buick Lesabre 3.8 4T60E. Also, can anyone explain the difference between a 777 and 775? Thanks

Where did you find it? Tranny OK?

Hmmm, no idea what it is, hopefully someone may recognize it. Was it found on floor under transmission?
Sure like the last photo, it makes for a cute paper weight.

Yes, on the floor after pulling the transmission. Cant seem to find the hole to put the puzzle piece. thanks

Are you rebuilding the trans or having a shop do it? If shop, hand them back the mystery part. It would be good to know where it'* coming from.

No one to blame except me, and Im not rebuilding the trans, Im swapping. If this part belongs to it, its from the outside somewhere,
thats why Im stumped, cant be that many places it could be from. Unless, it was laying on top of the trans from some other repair and fell off when the trans was removed. Ive been calling it my plutonium space modulator, and I will find out it goes between the trans and motor, is vitally necessary, as soon as I get everything back together without it.