[Jcom7777777]

Hello everyone.

I have an issue that can hopefully be solved by this forum and its great members.

I will get right to the main issue. When the transmission filter was removed, a small push pin fell out. There was also rounded plastic chunks in the bottom of the tranny pan. I would like to determine what this pin is, what the plastic might have come from, and where the pin is supposed to be.

Now some background...

1992 300D 2.5 Turbo
722.4 Transmission
210,000 miles

While leaving from a stop, I began to accelerate. About 1 second later the car stopped accelerating. Upon shifting into 2, 3, and D no motion only engine reving. I was able to shift into reverse and backed the car home about a mile. I purchased the car about 6 months ago and it has been a daily driver with NO transmission issues whatsoever, until now.

I did some research and thought the B2 Piston might be the culprit. I have attached pictures of the B2 piston and the push pin that fell out.

Of the 2 pins in the picture, the SMALLER pin is the one that randomly fell. The other pin was securly in with the piston.

The piston is entact and not in 2 pieces, so I do not think the whole B2 Piston issue is the cause for my problem...the new issue is this random small pin/rod that fell when taking out the transmission filter.

Any advice would be greatly appreciated.
Happy Driving.

 

[Jcom7777777]

Thank you for the info. A couple questions about your response:

Do you have any idea if the smaller pin butts up against plastic? I am wondering where the plastic chunks may have come from.

Also, If I was to get a longer pin in place of the piston pin, is this to take up space which was once occupied by the broken plastic?

Would a longer piston side pin cause misalignment?

 

[Jcom7777777]

I went to the dealership and purchased a new small pin, 2 longer pins of different sizes, and a spacer.

The longer pins came an about 5 different sizes. The short pin only came in one size. The spacer looks like it fits between the small pin and the brake band.

The parts cost $21.20 and should be here on Tuesday. I hope this solves the problem. Ill write a follow-up post when the job is complete.

 

[Jcom7777777]

Fixed

This is where the smaller pin fell out of. After installing all the new parts, the car is driving great. No problems. Thanks for the help guys, couldnt have done it without ya!

 

[Jcom7777777]

BenzHell,
I do not have any sort of picture tutorial. But I do have a pdf file that shows how to disassemble and reassemble the transmission valve body...BUT I will need to search for it and I am not home at the moment.

My car did the same problem, reverse worked - but no drive in any gears. I thought it was the B2 piston issue, but upon checking, it was not. The push pin was the culprit.

If you take the transmission mount off and push the transmission over to the side, you can access the b2 piston area. You will need to take off a snap ring then a cap. Then the piston will come out.

If you discover that the piston is still good, your problem is most likely the same issue I had. You will have to drain the transmission fluid, take the pan off, take out the filter, then take off the valve body. The whole time you should be looking for that push pin that might have fallen out. If you find the pin, go to the dealership and purchase a new small pin, the plastic spacer, and a new adjustment rod. The adjustment rod comes in multiple sizes. I cannot accuratly tell you what size to purchase, just get something larger than what you originally had.

That should do the trick. You might as well get a new transmission filter and seal while your at it.

Ill look for that pdf file.

Good Luck.