So a few days ago I noticed on the freeway every once in a while OD would feel like it was slipping into neutral. After a couple of occurrences I decided to take it to a transmission shop. Now, I live in Bend, Oregon but happened to be in Thousand Oaks, California. When the mechanic took off the transmission pan he showed me a piece of a snap ring had busted off from somewhere and was on the magnet in the pan. He wanted $750 just for the labor to take the transmission apart and see what was going on. He then said it would likely need a rebuild, for an additional $2,100. We decided to chance it and limp it home. We made, nearly 900 miles later, and during the drive back we had zero issues with the slippage... He left the piece of metal in the pan and didn't charge us, so today I took the pan off to inspect the metal piece. I can't figure out where it came from. I haven't yet removed the valve body and have never done so, I'm pretty nervous I'm going to mess something up. The van has the 4r70w transmission. I added a photo with a quarter for size reference. This thing must be pretty big and whatever broke it off bent it as well, does anyone have any clue where this thing came from?

 

It probably is part of a snap ring that holds one of the clutches together. I've seen transmissions run a long time with a piece of snap ring missing. I've also seen them come apart shortly after this happens.

Why are you going to take the valve body off? What do you hope to gain by doing that?

 

I guess I was hoping I'd be able to find where the snap ring came from and simply replace it for $5 instead of paying a shop hundreds just to look at it and thousands more to fix it.

I decided not to take it off and just put the pan back on and am going to refill. I think I'll probably wait until Monday and bring it to the tranny shop in town for an opinion. I found a local independent guy who will rebuild it for $1k so there's always that...

 

You can't get to the snap ring by taking off the valve body. To get to the snap ring you need to take the trans out and tear it down.

 

wow.well the fact it broke off like that means rather than coming out of its groove,it just lost an end.so lucky you lol.
run 'er for all she's worth.the snap ring's other 90% could remain where it belongs and could outlast the van.