W124 Gearbox urgent advice needed

[roadhog]

Hi all, further to my thread about my auto gearbox losing all forward gears http://forums.mercedesclub.org.uk/showthread.php?t=33083 I decided to open the box up. I've spent most of today stripping and cleaning the valve body assy. I even managed to get it back together without any spare parts!
Just as I was about to put the sump back on I thought I'd take the filter off just to make sure it was OK. That's when it happened....
As I lowered the filter something tinkled into the tray I'd put under the gearbox. The something turned out to be a pin, approx one inch long with a ball end either end.
My problem is, I can't for the life of me work out where it came from. The only place that looks vaguely possible is the cylindrical protrusion near the top left of this picture http://i152.photobucket.com/albums/s173/roadhog_photos/100_0952.jpg
It will fit in one way only, one of the ball ends is slightly larger than the other and once in looks like this http://i152.photobucket.com/albums/s173/roadhog_photos/100_0957.jpg
Once in there though, there's nothing to hold it in place so I'm not sure it's right.
HELP! PLEASE!

 

[Richard Moakes]

Looks very similar to your problem?

http://www.mercedesshop.com/shopforum/showthread.php?t=175341&highlight=transmission+drop+pin

It's a reaction pin, engages with a brake band (B2, B3 etc...), I had to refit one when I replaced the Overload Protection Switch, it was held in place by a plastic collar. Did you remove any of the plugs on the side of the tranny whilst you had the valve block removed?

In fact I am sure its connected with your loss of forward drive, without it the brake band will not operate correctly, indirectly I think you have found the original problem. Now we just need to reassemble it !

Good Luck,

 

[roadhog]

Thanks Richard, why didn't I find that yesterday? I've had to go back to work for now so had to stop on the gearbox.
That looks like the same pin as mine, doesn't say why it fell out though. B2 Brake band would explain my problem, sadly it looks like the pin is the wrong side of the band to pop back in by removing the piston from the outside?
If I'd removed the filter first I wouldn't have spent a whole day stripping the valve body. Thanks to your pdf I managed to get it back together and it was very educational

 

[Richard Moakes]

Been searching more info....

http://www.mercedesshop.com/shopforum/showthread.php?t=173524&highlight=b-2+reaction
http://www.mercedesshop.com/shopforum/showthread.php?t=30471&highlight=b-2+band

After reading numerous posts on this, I am convinced you have got a failed B-2 band which has led to the reaction pin falling into the filter.

I can't help feeling you will need to drop the transmission to sort this out now.

Good Luck,