'80 300D transmission adjustment - PeachParts Mercedes-Benz Forum

fahrgewehr2 · #1 12-28-2005, 04:35 PM

Have the 2-3 flare on my '80 300D. Transmission shifts VERY softly- softer than my 300SE. Besides the 2-3 shift, there is not flaring.

Some of you guys have replaced the k1 spring to fix this problem, but this car doesn't have that, or a modulator.

How do I adjust it so all gears shift firmly?

Lots of info in the archive, but all seem to address the later models.

Thanks.

fahrgewehr2 · #2 12-28-2005, 09:44 PM

anyone?

diesel don · #3 12-28-2005, 10:09 PM

Look under 'flaring' with 'diesel don' and you'll find an article by Steve Brotherton (or similar spelling). I think his article was for multiple models. Extremely thorough. My first thots include:

1. the cable
2. the vacuum feed (not even sure this is accurate on an '80)
3. modulator on the driver's side of the tranny (again, might be wrong model)

On one of my cars, I simply had to live with it. Hammering down on the pedal sure helped. The cars tend to want to flare when you're going easy on the acceleration.

let me know via email if you can't find the article

dp

JimmyL · #4 12-28-2005, 10:09 PM

Quote:

Originally Posted by fahrgewehr2

Have the 2-3 flare on my '80 300D. Transmission shifts VERY softly- softer than my 300SE. Besides the 2-3 shift, there is not flaring.

Some of you guys have replaced the k1 spring to fix this problem, but this car doesn't have that, or a modulator.

How do I adjust it so all gears shift firmly?

Lots of info in the archive, but all seem to address the later models.

Thanks.

Been there, done that! Your modulator is on the passenger side of the tranny. I'll attach a pic of the one from my old '80 wagon. It is red and the pic is when I was laying upside down under the car. You remove a cover on the end with pliers by crimping a ring-type clip holding it in place. When removed there is a metal tab inside the modulator that fits in different grooves. You will understand when you see. Clockwise for firmer/later shifts on this model. Actually more for the shift point than for the firmness.
There was a 3/2 valve on the valve cover that sent vacuum to the tranny modulator. The more vacuum, the sooner the shift. Vacuum is what makes the shift. I had to mess with the vacuum to the modulator, then mess with the modulator. As the throttle/linkage travel increases (more force on accel. pedal) the vacuum to the modulator should decrease. It will require some "messing with", and trial and error. Only move tranny modulator tab one notch at a time. I would pull up on ramps, make an adjustment, back off the ramps and drive down the road. Did this for quite some time before I got it right. Ended up perfect though. The smoker had it's issues, but shifted perfectly!

Miss that car........

linguica · #5 12-28-2005, 10:34 PM

Quote:

Originally Posted by fahrgewehr2

Have the 2-3 flare on my '80 300D. Transmission shifts VERY softly- softer than my 300SE. Besides the 2-3 shift, there is not flaring.

Some of you guys have replaced the k1 spring to fix this problem, but this car doesn't have that, or a modulator.

How do I adjust it so all gears shift firmly?

Lots of info in the archive, but all seem to address the later models.

Thanks.

I have the exact same trans. symptom on my 85 300d. Getting ready to change fluid and filter(as soon as my back straightens out). The color is looking brown/rust and no record of when it was last done...might try some trans-x until then. If that doesn't get me anywhere, then I will pursue other options.

fahrgewehr2 · #6 12-28-2005, 11:26 PM

Thanks for the replies.

http://www.continentalimports.com/ser_ic20242.html

(article link, for others watching this thread)

I'll check out my setup and report back.

biopete · #7 01-07-2006, 04:36 PM

Quote:

Originally Posted by diesel don

On one of my cars, I simply had to live with it. Hammering down on the pedal sure helped. The cars tend to want to flare when you're going easy on the acceleration.

dp

Just throwing this out here while I research. I have read some of the articles and post s on flareing and have not seen anyone mention flare with more accelaration. Here's my situation ;

1981 300D NA(non turbo) -- Shifts smooth as glass with my foot barely on the accelartor. I can normally never feel it shift from 1 to 2. It flares like mad if I hammer down on the pedal (Very annoying and dangerous when pulling out into traffic). . Taking my foot off the pedal (which I sometimes have to do) causes it to kick into grear instantly.

So, I am deducing my flare has something to do with the position of the throttle. Reading on "flare'' , I realize that could be linkage or vacuum right? Or are these mutually exclusive ?

Thanks

fahrgewehr2 · #8 03-28-2006, 09:44 PM

Found the modulator, but I hesitate to adjust it if the problem can be solved with a K1 kit.

This link which was posted by a forum member says the kit is good for 722.3 trannies.

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=2&Product_Code=S68165D

How do I find out which tranny I have in my diesel?

JimmyL · #9 03-28-2006, 10:35 PM

Quote:

Originally Posted by fahrgewehr2

Found the modulator, but I hesitate to adjust it if the problem can be solved with a K1 kit.

This link which was posted by a forum member says the kit is good for 722.3 trannies.

http://www.bulkpart.com/Merchant2/merchant.mvc?Screen=PROD&Store_Code=2&Product_Code=S68165D

How do I find out which tranny I have in my diesel?

My guess is you have the 722.1xx tranny. Somebody else will be able to tell you how to tell.
I again just offer my explanation above. Not the most thorough I guess, but it worked well. Just keep track of which way and how many times you turn the modulator pin. Document everything you do, everything you change. That way you can always go back to the starting point and try something differently.

fahrgewehr2 · #10 03-28-2006, 10:41 PM

Thanks for your replies Jimmy.

I will call the dealer with my VIN number and see if they can tell me.

If the K1 kit is not applicable to my car, I will follow your instructions.

Thanks for your help.

rs899 · #11 03-29-2006, 06:15 AM

Easiest way to tell a 722.1xx from a 722.3xx is just to look at the fluid pan. The former has 4 bolts retaining it, the latter 6 bolts.

Rick

linguica · #12 07-09-2006, 10:21 PM

Quote:

Originally Posted by linguica

I have the exact same trans. symptom on my 85 300d. Getting ready to change fluid and filter(as soon as my back straightens out). The color is looking brown/rust and no record of when it was last done...might try some trans-x until then. If that doesn't get me anywhere, then I will pursue other options.

I ran 2 cans of trans-x for about 1000 miles. Today I changed fluid, filter and k1 kit. Shifts great!

shadetreetech · #13 07-10-2006, 01:22 AM

well maybe this helps .I had a bad flare recently wich went away after reconnecting the piece of linkage that connects throttl linkage to that vacume unit on the back of fuel injection pump now she shift really firm

rhodes2010 · #14 07-10-2006, 02:09 PM

My 1980 300D (which I have owned since 1984) has
had a nasty flare on 2-3 shift for more than a decade....
until now. It shifts better than it ever has after I replaced
the little valve on top of the engine with the vacuum lines running to it.

Unlike other models with a cover over the valve, my 300D has a very visible
valve and some vacuum lines.

I tested the valve with a vaccum pump (mighty-vac type) and compared the results to a brand new one I happened to have.
It was clear the old one leaked. The new valve is easily $30 to $45 and
can be bought here through Fastlane or from your dealer.

Originally I was going to only replace the worn out valve lever ( a $3 item),
but decided to check the valve while in there, really glad I did.

Here is my post on the subject :

2-3 Flare on Shift - replaced 3 way valve.

linguica · #15 07-10-2006, 07:54 PM

Quote:

Originally Posted by rhodes2010

My 1980 300D (which I have owned since 1984) has
had a nasty flare on 2-3 shift for more than a decade....
until now. It shifts better than it ever has after I replaced
the little valve on top of the engine with the vacuum lines running to it.

Unlike other models with a cover over the valve, my 300D has a very visible
valve and some vacuum lines.

I tested the valve with a vaccum pump (mighty-vac type) and compared the results to a brand new one I happened to have.
It was clear the old one leaked. The new valve is easily $30 to $45 and
can be bought here through Fastlane or from your dealer.

Originally I was going to only replace the worn out valve lever ( a $3 item),
but decided to check the valve while in there, really glad I did.

Here is my post on the subject :

2-3 Flare on Shift - replaced 3 way valve.

My car is a '85 300D Cali. I does not have the vac. valves you are talking about, so I was pretty sure the k1 was the problem...and it sure was

.

Mark