Of course, the pin broke yesterday when I removed the old modulator for replacement. Trouble is, it broke off very near the end such that the piece is recessed in the inside sleeve that it rides in. Forget tweezers, needle noses, etc--I can't even see the end using a mirror.

I put a dab of RTV on the end of the outer piece and put it back in against the broken piece thinking that they may adhere enough to allow me to pull it out. I am now waiting for it to cure. If that doesn't work, I may try super glue. Failing that, a hot wire.

I have an exploded view of the modulator that shows the pin going inside a sleeve inside the trans. Is this removable from the outside? If so, how?

It was suggested in an old thread that I may have to pull the valve body to get at the piece. Is that so? How does the VB attach to the bottom of the trans? What do I need to watch out for if I pull it, other than the little metal pawl that Whunter warned about?

Here's a thought--since the pin is a push rod, could I just shorten the new pin and leave the broken piece in the trans?

Thank you for your interest.

Would a tiny magnet help?

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
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"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970

I had a similar experience on mine a few year ago.(I believe mine may have been broken by PO/mechanic) Fortunately, I was able to grab the end of the broken piece with curved needle nose pliers.

Don't modify the new pin as it will result in very erratic shifting. The broken pin in mine caused very crazy shifting patterns.

Using RTV is a very risky suggestion as the slightest bit of it can cause much transmission grief. The hot wire may work but the pin is made of a material for a hot temp environment so I doubt it will melt. Probably the best suggestion is removing the valve body, which you may have to do anyway if any of that RTV ends up in the tranny.

I personally have not removed the valve body but here are many threads and posts from folks that have:Transmission:

Once you have it resolved, then you have the adjustment procedure to deal with. That's why I've tried to steer folks toward changing the modulator as a last resort, after it's confirmed to be the problem (leaking). On these cars, modulator replacement is sort of a PIA, as they are not just a plug-n-play component.

__________________
Sam

84 300SD 350K+ miles ( Blue Belle )

Considering that it broke, we are probably dealing with a plastic pin here. But the "make and model" mysteries do make it a challenge to give appropriate advice.

What model "trans" are you working on?

Sorry about that. It's a 1981 300TD with a 722.303 transmission.

Yes, the pin is plastic so a magnet wouldn't work. The RTV didn't adhere. I only used a miniscule amount and the sleeve the pin resides in would keep it from getting into the trans anyway. I imagine there was a film of trans fluid that kept it from bonding.

In the end, I was able to pull the sleeve with the broken piece inside by using an easy-out very gently to bring it out far enough to get a pair of offset needle nose pliers on it. Problem solved, albeit with a lot of teeth gnashing.

The reason I am changing the modulator is because trans fluid was entering the vacuum system and it was not holding vacuum.

Thanks to you all for your help.

Same thing happened to me on my SD. I had one of those cheap sets of awls or whatever they are from harbor freight, and one of them had a curved end sort of like a dentists pick and I was able to fish it out. If you can't fish it out maybe you could try using the end of a vacuum to suck it out.