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  #1  
Old 12-24-2009, 01:13 PM
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Red face Vacuum Modulator Cap "Stuck"...

OK, Here's the story. I recently had a rebuilt transmission installed in my 300SD. It was shifting a little hard, so I got up under the car today to back off on the vacuum. When I popped the black plastic cover off, it fell down into an area behind a metal assembly, a little over an inch behind the modulator. I don't have a floor jack or ramps, so I am working with the car on the ground. I can feel the cap with my fingers, but cannot grasp it due to the tight area. The fact that I am right-handed and have to use my left hand hasn't helped. I have also tried using a short screwdriver to pop it out, two types of needle-nosed pliers to grab it, and even used duct tape to try and get a hold of it, to no avail.

Anybody have any other ideas??

I have a piece of duct tape over the modulator right now so I won't lose the metal adjuster, but I want to get this sorted out properly...

Kind of reminds me of the saying: "Do not try this at home. We are professionals..."

Merry Christmas!
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Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
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Wife's: 2008 MB C300 Sport - 82K mi (April 2009)
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  #2  
Old 12-24-2009, 01:33 PM
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push a piece of duct tape in there and hop it sticks to the cap so you can work it out? Use a piece of wire to move it partways, then grab it? Put one side of car up on curb to get a bit more clearance underneath? All fun stuff on Christmas eve
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  #3  
Old 12-24-2009, 01:34 PM
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How about a pair of tweezers, or a pair of hemostats?
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  #4  
Old 12-24-2009, 01:43 PM
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It's cold and raining right now so I'll have to try the curb thing later.

Already tried the duct tape twice unsuccessfully, and one of the "needle-nosed" pliers was actually a hemostat... I also did try small tweezers, but couldn't maneuver...

Once the weather breaks, I'll get back at it again.

Thanks, guys!
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Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
Mine:1981 MB 300SD - 326K mi (July 1997)-sold
Mine:1994 Ford F-150 - 200K+ (Dec 2015)
Wife's: 2008 MB C300 Sport - 82K mi (April 2009)
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  #5  
Old 12-24-2009, 02:08 PM
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You also could buy another Cap.
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  #6  
Old 12-24-2009, 02:13 PM
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Buying another cap (or two!) is probably the best use of my time.

A $2 part versus value of my time = no brainer.

Sometimes I just like the challenge of finishing a job 'on time and under budget'...
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Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
Mine:1981 MB 300SD - 326K mi (July 1997)-sold
Mine:1994 Ford F-150 - 200K+ (Dec 2015)
Wife's: 2008 MB C300 Sport - 82K mi (April 2009)
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  #7  
Old 12-24-2009, 02:43 PM
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Quote:
Originally Posted by dcotejr View Post
It was shifting a little hard, so I got up under the car today to back off on the vacuum.
"Backing off" on the vacuum will make the shifts even harder. Which is not to say that the vacuum can be adjusted at the modulator.
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  #8  
Old 12-24-2009, 03:10 PM
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Try a shop vac

The almighty blessed me with paws, not piano fingers, not enabling me to get at everything I drop () I've found two ways to work around this --- suck it out or blow it out. Recommend you clean out the shop vac receptacle BEFORE using it. Compressed air works too....wear eye protection and I found it good to have a spotter to see where the piece will fly off to.
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  #9  
Old 12-24-2009, 06:25 PM
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Tango - 'backing off' may have been a poor choice of words. I rotated the pin CCW to 'soften' the shifting...

300Downer - I like the shop vac idea - I could actually use a piece of my wife's old nylons to prevent it from entering the vac... I'll see if I can fit it up into the area.....
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  #10  
Old 12-24-2009, 08:10 PM
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Quote:
Originally Posted by dcotejr View Post
Tango - 'backing off' may have been a poor choice of words. I rotated the pin CCW to 'soften' the shifting...
Nothing should be adjusted with regard to the modulator pressure without a gauge. It's the adjustment of last resort.

Hard shifting is corrected by increasing vacuum to the modulator or finding and curing the likely vacuum leaks to the EGR system.

If you've read any of the archives on the vacuum system, you'd understand that your approach is completely in error.
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  #11  
Old 12-26-2009, 03:30 PM
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Brian - my approach was based on the following document. I purchased a rebuilt tranny from Sun Valley, and had it installed by a local indy. This came with the paperwork I received...

Is this completely wrong?
Attached Thumbnails
Vacuum Modulator Cap "Stuck"...-transmission.jpg  
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Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
Mine:1981 MB 300SD - 326K mi (July 1997)-sold
Mine:1994 Ford F-150 - 200K+ (Dec 2015)
Wife's: 2008 MB C300 Sport - 82K mi (April 2009)
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  #12  
Old 12-26-2009, 03:44 PM
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Quote:
Originally Posted by dcotejr View Post
Brian - my approach was based on the following document. I purchased a rebuilt tranny from Sun Valley, and had it installed by a local indy. This came with the paperwork I received...

Is this completely wrong?
Is it completely wrong? No.

Does it go to a place that shouldn't be adjusted until all efforts have been made with regard to the vacuum system? Yes.

If the vacuum system is not performing correctly, any adjustment to the modulator will be meaningless. Furthermore, you'll get yourself "lost" because the modulator has no defined position unless a pressure gauge is utilized.

The proper approach by Sun Valley should have been to set the modulator with a pressure gauge and then direct the owner/purchaser to adjust the vacuum to the modulator to correct any shift quality issues. But, Sun Valley doesn't want to address the vacuum adjustments because they probably don't know how to do it.
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  #13  
Old 12-26-2009, 03:54 PM
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Thumbs up

Thanks, Brian. Looks like I need to take a step back. I've got a small mityVac, so I will read the links and try to go through it from the beginning...

I'm still kinda new to some of the hands-on repairs and maintenance for this vehicle...
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Mine:1991 MB 350SDL - 244K (Aug 2011)- Totalled 9/14/2016
Mine:1981 MB 300SD - 326K mi (July 1997)-sold
Mine:1994 Ford F-150 - 200K+ (Dec 2015)
Wife's: 2008 MB C300 Sport - 82K mi (April 2009)
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  #14  
Old 12-26-2009, 05:45 PM
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Quote:
Originally Posted by dcotejr View Post
Brian - my approach was based on the following document. I purchased a rebuilt tranny from Sun Valley, and had it installed by a local indy. This came with the paperwork I received...

Is this completely wrong?
Note the very first sentence in the instructions. The one with the line underneath it.
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