OK, so I'm nothing but a little dangerous when it comes to transmissions. Fine with the engine and anything else, just nothing but filter and fluid changes when it comes to transmissions. I was changing the filter and ATF in my 1996 C280 this afternoon, nothing unusual until I dropped the pan and these fell out (see photo).

What are they, how do I fix it, is the tranny even worth trying to save? I am stopping work until I can find out what the heck this is. Thanks.

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They look suspiciously like bits from the valve body.

Did any function of the transmission cease to work?
How about a pic of the pieces with a common object of similar size alongside them for scale.

Given the scale of the machining marks, I'd say the pin is 5/16" ish dia and about an inch long. It looks like a pin between a band apply piston and band or band and anchor point. The circular item looks like a now worn clip that keeps the band apply pin from falling out during assembly.

I don't have a parts chart for the .4 but do have one for the .5 5 speed.

If the scale of the parts drawing is to be believed, have a look at parts 272 for the pin on the anchor side, 277 for the clip on the apply piston side. These are part of the B2 rear band.

If the trans operated normally, I'd say someone changed the band apply piston ( accessible from outside the trans ) at some point and the parts fell into the pan.

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I guess that I forgot to mention - Would not start in 1st gear, barely moved and revved high. If I let off the accelerator, it would catch in I guess 2nd gear. Once moving, it shifted normally. This had happened once before about 4 years ago and the shop looked it over and just said that it needed new ATF and filter. Been going along just fine ever since then.

I have read some about the B2 piston - How do I remove and replace the piston, or is this a part that I can service without removing the piston?

Here is an apply chart for the .3 ( same operation as the .4 )

http://www.peachparts.com/shopforum/tech-help/377991-190e-wont-move-1st-reverse.html

Many of these trans start out in 2nd and you are probably forcing it to start out in 1st where the "freewheeling unit" ( sprag , one way clutch ) and B2 are in operation. If you have a weak B1, starting out in 1st might lighten the load enough that a slipping B1 will still hold long enough to get to 3 rd.

Regardless, a missing band apply pin can't be fixed with a fluid change and won't cause a slipping condition so you probably have other problems. Try to shift manually and take detailed notes.

here is the B2

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