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  #1  
Old 11-29-2003, 08:03 PM
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83 300D Trans issue

Some of you may have followed the posting of a friend that had an 83SD, from which I pulled some interior parts.

On the one hand he needed a new ride and doesn't have any cash to work with and on the other hand my uncle has an "extra" 300D that he bought and got stuck because of a transmission problem. He didn't seek me out before buying it.

So I am trying to help them both out by a deal between my friend and uncle with me doing the work to get the car right, to help them both out

The issue.

The transmission does not shift from first until very high RPM and when it does it skips 2nd and goes to 3rd.

I checked the vacuum to the modulator and it holds and loosened up the downshift cable. I also manually checked the downshift switch at the accelerator to see if it was stuck down. All to no avail as it continues to have the same issues.

Any one have any ideas?

Thanks
Don

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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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Old 11-30-2003, 10:30 AM
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tht
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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  #3  
Old 11-30-2003, 10:43 AM
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My 83 does the same thing, as well as flaring when it shifts into 4th. As I understand it, this is due to worn clutch surfaces and valve body seals causing pressure losses to the valves in the body that do the actual gear changes. There is a spring kit available to sovle the 1st to 3rd problem, a search here may yield the MB pn, I'll look thru my notes to see if I can find it. I haven't tried it, I'll be rebuilding the tranny come spring instead.

Jerry
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Old 11-30-2003, 10:59 AM
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If it is valve body related, then I wonder if it makes sense to drop that and fix it without a re-build. I have no idea if it flairs because the shifts are so out of wack from an RPM standpoint.

Never been inside one of these. Is there a kit for rebuilding it?

I wonder if the valve body from an 83SD will go into it? I have a good 83SD trans still in a donor car.

Thanks for taking the time to help.
Don
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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  #5  
Old 12-01-2003, 07:12 AM
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As far as I can tell the valve bodies are the same. The difference appears to be in the tail housing, electrical speed sensor in the 126 vs mechanical in the 123. Fastlane does list a reduild kit that also contains friction material. Precision International puts together kits as well.

Good Luck
Jerry
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Old 12-01-2003, 11:52 AM
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Thanks

Don
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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  #7  
Old 12-01-2003, 07:22 PM
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I had the exact same problem. I took the car to the shop for it's initial valve adj; fuel filters; and tranny fluid/filter change; before a cross-country drive.

It took a half-day of trial and error, but I ended up with a smooth shifting car. BUT, now it almost always starts in first, not second, unless it's really warm and on just the right incline.

I think they worked on the linkage to effect this change.
I don't know much about the linkage, but when I said how I liked the way it goes easily from gear to gear, but wished it started in second, they basically said I could have one or the other. Overall, I'm pretty happy with how it's running....
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1983 300D- silver blue, tan leather, 205,000.
1975 Datsun 280Z. Stock, ready to restore.
1983 San Juan 23. Dry docked.
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Old 12-01-2003, 09:15 PM
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As I understand it....

Our transmissions are suppose to shift into 2nd when we are at a dead stop to avoid creeping forward. That as soon as you even slightly touch the accelerator (or release the brake), it goes into first without any noticeable actions. That it should begin its driveoff in first.

In my case I don't think it is linkage, vacuum or cable adjustment. I think it is either gummed up or has a problem with the valve body. Being that it is quick to go into drive or reverse, does not leak and at times shifts correctly, the issue must be something that controls an action rather than a part that carries out an action. So the 'brain" seems to be confused. Now I suppose the pump might be weak, however I find that a difficult conclusion as the 3rd to 4th and 4th to 3rd is fine.

Who knows, it could be as simple as a fluid change which I am planning to do next. I read on this forum about Trans-X, so I am going to toss some of that in as well.

I think transmissions are those things we have in our cars and are use to them working or not. When not, they are rebuilt. Being a bit older and wiser, I find that a blanket cure that is simular to rebuilding an engine because it is running rough. Sure a rebuilt motor will take care of the problem, however it might have only been a valve adjustment. So I am in this to uncover the mystery of it all and hope to fix what is not working rather than replace the whole thing cause it's spooky in there!

Don

Thanks for the suggestions and keep um coming!
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1980 300TD-T (82 Turbo and Trans) 159,000 Miles "Jackie-O"
1983 300SD 272,000 Miles "Aristotle"
1987 Jeep Wagoneer Limited - keeps the MB's off the ice and out of the snow
1994 BMW 530it
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  #9  
Old 12-01-2003, 09:37 PM
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Don

The following describes my journey and the data I've collected since trying to solve my "flaring" problem between 2-3. Much of it is the same for tranmission adjustment.

The most comprehensive discussion on this is from Steve Brotherton (some kind of tech) who seems to know these trannys inside and out. Perhaps as much as 6 factors need to be in balance for the trannys to shift properly. I have made great improvement even though its not perfect yet. My final adjustment is where I simply ran the car without vacuum to the tranny. Hard shifts but no flaring.

Regardless of your particular issue, you'll find this printout invaluable.

His information (5 page printout) is available at:

www.continentalimports.com

click on "articles" and then "mercedes-benz transmissions".

He has pics and the whole shootin' match.

Don
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'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
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  #10  
Old 12-01-2003, 09:40 PM
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Don
thanks very much for the link...

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1983 300D- silver blue, tan leather, 205,000.
1975 Datsun 280Z. Stock, ready to restore.
1983 San Juan 23. Dry docked.
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