last week I was wrestling with the keep the car or junk it question seethat old thread .Well i got the pan apart convinced that I have the B2 piston problem. ( for refrence see this and this )

After much aggravation pulling the retaining ring out I am ready to diagnose. The piston did not fall out in my hand as had been described by others with the problem. Does this mean that is is still intact and not the problem. The piston does not appear that it wants to come out at all.
[IMG]
I did notice however that there is a vacuum line that is broken nearby. Arrow #1 in the picture points to this line. Maybee I broke this today or maybee it broke before and that is why I was stuck? Am I being overly optimistic? Would this line being broken keep the transmission from working.
Arrow #2 points to the piston.
P.S. Heaps of metal shavings in the trans oil pan.

Attached Thumbnails

 

Anyone?

There are no vacuum lines whether disconnected, plugged or whatever that will keep these transmissions from shifting. The vacuum on these only soften or slow the shifts. With no vacuum the trans will shift quicker and harder.
With the presence of metal shavings you may consider replacing with a rebuilt or used? Those chunks will destroy the front pump. That pump costs about $850 just for the part, if you can find one.
I would guess the B2B is broke. It should pry out of there. It is a big piston and it can get hung up on the metal parts that fracture. Just push, pull, pry it out.

Thanks Old Dies. Yeah with that many metal shavings the trans is probably cooked and there is no reason to hesitate prying on the b2 piston. I worked it a while and it did not seem to want to come out which make me think that it was not broken.
I put a couple of the parts in the dishwasher last night to get the metal shavings off. It worked great

I have always wanted to set up a dishwasher in the garage, using a small hot pass through hot water heater, to clean auto parts. Figure find a cheap one used. Then the waste plumbing. hmmm.
Friend of mine used to wash parts in his. Nice and clean. That worked right up to the night his dear ex wife came home early. Caused a real ruckus.
Still, it was a great way to get them super clean. And who needs a wife with that going for him?

yeah, except for oil trapped in little passages that might drip out as you are pulling it out you could get all the evidence out of there and there would be no way of knowing anything went on. The inside of the washer is just as clean as after a load of dishes. I do this when I hone the cylinder of my motocross bike to get any residual metal out. In this case I put the trans filter through the washer and it looks good to go.

Back to the piston. I have continued to wedge, hammer from the inside, etc and this thing is not moving. I have taken the plastic piece off that you see at the arrow #2 in the picture above and wedged on the lip hard enough to chip the metal off and it is still not coming out. I do not see anything reachable on the inside like a clip that could be holding me up. What is going on? This has got to be the b2 piston right. It is the closest to the rear on the passenger side. My car is a 79, does this b2 stuff not apply to my car?

That trans looks a lot different than the one in my car. My B2 piston was not like what you are identifying either. Sorry I can't help

__________________
'82 300SD - 361K mi - "Blue"

"Good judgement comes from experience. Experience comes from bad judgement."

listen, look, .........and duck.

I am not 100% on your 79, but have been told that one should have the same B2B as ny 81. Your pic wa a little dark, seems to appear different than the B2B in my 81.
Have some photos of the B2B but I cannot get this foul new program to cooperate. After removing the circlip and the round cover your should be able to pull it right out. It is the large round cover on the rt rear of the trans. Has a smooth round metal cover, B2B is under that. Biggest round cover on the tranny.

here is a better pic of that location.[IMG]

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http://ac.unpatented.com/pics/trans/oldtransmission.jpg
Maybe you can read this?
That pic looks pretty much like a B2B, same shape-size and location as what I had seen. Just yellow instead of aluminum.
I see it is part way out. My guess would be that the metal shaving are jammed in between the piston flange and the walls around it. If you do not intend to save the B2B you might use a pipe wrench to spin it around and get it out. Maybe use a rag to protect it from the wrench. There is a dogbone behind the B2B that is pushed by the B2B into the band. The B2B is supposed to slide freely in the cylinder there. The band keeps tension on the dogbone,which in turn pushes the B2B into the round cover.
http://ac.unpatented.com/pics/trans/b2bpiston3.jpg

I dont know how much more Ive got in me before I go at the whole thing with a hammer. This is my third full afternoon and evening under it and I am getting pretty clausterphobic. Thanks for all the good help. Old Dies. from your pics I am in the right place. I can not get the thing to go out and now it won't even go back in. I fabricated a tool to compress it and it will not go but a few millimeteres. It will spin freely around if that is an indicator of anything. I can not figure out what the dog bone is. Enclosed is a picture of the inside of the tranny.
The picture the phil at fastlane sent me is for the serial number of my tranny but things dont seem to match it exactly.

for those reading old threads here is the diagnosis. It was not the B2 piston. I was finally able to remove the piston by compressing it in with a modified c clamp I made and then it then finally came out intact. So I am pronouncing her dead here at 12:40am. For the cost of a transmission replacement I am just going to have to get another car. For sale one 79 300sd parts car in great shape except for transmission. Want to buy 80-85 300sd. 2 hour radius of Chatt. TN. Thank everyone for their help. If I had it all to do over again I would have given the car a name on the first day. Cars with names never seem to die.

Sorry to hear that it is ruined. Just for your info, part #299 in the diagram is the dogbone. It is laying in the front of this photo, next to my broken B2B.
http://ac.unpatented.com/pics/trans/b2bpiston.jpg