Hello
I have searched far and wide for an answer to this. There are lots of posts about the 2-3 flare, but I cannot find anything about a 1-2 flare. I have a new modulator, simplified vacuum (no climate control: it is controlled by a ball valve and fan switch; no central locking), and replaced the K1 spring which made my 2-3 shift feel almost non-existent.
However, I have a bad flair between 1 and 2. Is there a spring I can change to correct this? I have adjusted my modulator and bowden cable to no avail.
Is it maybe my B2 piston?
Any ideas?

Do a search for Trans-x ... using my name.... could be built up varnish in the control passages... slowing the action of the clutches..

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Hmmm...I have flushed the trans twice with new filters and used a detergent the first time. However, I cannot remember what kind I used...

Mercedes-Benz Transmission terminology for dummies (722.XXX series transmissions)
I find that a lot of people immediately go to the internet and ask "why is my transmission not working" only to receive a number of seemingly cryptic answers filled with letters, numbers, and foreign terminology. Here is a quick crash-course on the most common terms and references when talking about these transmissions.

B1 - controls 2nd gear. A bad B1 band or piston will make the car shift from first to third.
B2 - most common failure in Mercedes transmissions for years, controls first gear, "shifting into drive"
B3 - reverse gear brake band. Some models of MB transmissions can be adjusted externally to reduce slipping and flaring when engaging reverse, others do not have this feature. If you have an older Mercedes with no reverse, the B3 is the most likely cause. I see this especially in the gas w124s and w201s for some reason, many many cars on the market with no reverse. This requires a trans rebuild to fix.
K1 spring - this is a spring in the valve body that controls the 2nd-to-3rd gear shift. Over time, both the K1 and K2 springs wear out and cause the transmission to flare a bit between shifts. There are "repair kits" available with new springs and seals for the DIYers, not a difficult fix. These springs actually control how the corresponding clutches (called K1 and K2 clutch packs) operate.
K2 spring - similar to K1 controls the 3rd-to-4th shift, along with reverse and overdrive.
"Flaring" - this refers to the RPMs spiking in between shifts under normal driving. This is usually caused by either overly-soft shifts (worn out springs and/or vacuum issues).
"slipping" - This means the car goes in and out of gear, typically creating a jerking motion under acceleration, sometimes also a bad jutter.

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92 e300d2.5t
01 e320
05 cdi
85 chev c10

A detergent ?
I have never heard of that being used .....
usually with oily fluids some sort of solvent is involved....


https://www.google.com/#q=detergent+definition
''''a water-soluble cleansing agent that combines with impurities and dirt to make them more soluble and differs from soap in not forming a scum with the salts in hard water.'''''

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

You don't remember engine oils being classified as "high-detergent" and "low-detergent" oils?

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Gone to the dark side

- Jeff

Yes , and I remember warnings on old tractors for instance which cautioned against changing from nondetergent to detergent oils... but as you can see from the usual definition of detergent that it involves water...
I do not think those detergent oils were using the term literally or chemically correctly ... but as a way to show they were different from the pre 1953 oils... which made no attempt to keep ' bad stuff' in suspension so it could be caught by either the oil filter OR be evacuated by using the drain plug...

but the inclusion of chemicals in an oily fluid is different from the concept of adding a ' detergent' to clean out that system.... which by normal definitions includes water.

http://www.explainthatstuff.com/detergents.html



https://www.fillingstation.com/articles/earlyengineoil.htm

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

otto:

Questions and opinions about chemistry quite aside, we may think that you have posted about a Mercedes car, but which one? Year, model, engine.

I suspect Otto is using the term detergent in a more general sense to mean something which cleans, some sort of cleaner additive.

I do also... just trying to get clear on the nomenclature being used...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

Indeed...I am using the term detergent in the most basic sense. I am sure it was some sort of solvent. My bad. I didn't mean to start a debate on chemotaxonomy .

Sorry not to mention the vehicle. I guess I got ahead of myself.
It is a 1983 300td.

Thanks for the run-down dieselbenz1. None of the info talks about the 1-2 shift, though. It is most definitely a flare. So is this probably a vacuum issue?
When I check vacuum from the VCV, should it go to zero when I give it throttle?

otto:

What are the speeds (MPH) at which the shifts occur with ~1/4 throttle, and with ~3/4 throttle?

Detergents are surfactants which can dissolve in solution. It could be an oil solution or a water solution. Calcium sulfonate is an example.

The first suspect is your "simplified" vacuum system. My guess is it's more like a "ruined" vacuum system. Of course, nobody has asked what car and transmission we're talking about. But let's assume it's a 722.3 or 722.4. You probably have, or maybe had, a blue vacuum amplifier. This is supposed modify the vacuum signal to give better shifting at low speeds.

Another possible culprit could be the bowden cable, which modifies working pressure at low loads. And finally, the B2 piston could be leaky or the band worn.

Finally, let's talk about how these transmissions work, rather than a magic cookbook of try me fixes:

Your transmission has two planetary gear sets (1 and 2 counting from the front), each capable of two forward speeds. Each gearset has a band to control the outer ring gear and a clutch pack to control the center (sun) gear. By combined action of the two bands (B1 and B2) and two clutches (K1 and K2), four speeds are possible. The bands and clutches that need to be applied are as follows:

1st gear B2 only
2nd gear B1 and B2 only
3rd gear K1 and B2 only
4th gear K1 and K2 only

There are lots of good animations and demos available on planetary (epicyclic) gearing:

https://www.youtube.com/watch?v=a1JAWoAvK-E

The "K" accumulator pistons and springs control the rate at which the clutch packs are pressurized. Sort of like feathering a shift on a manual car: too fast off the pedal, and the clutch pops, too slow and it slips. Which is why the K accumulators are suspect when there's an engagement problem 2-3 or 3-4. There's no equivalent function on the bands .

The speed is about 15 mph and it only flares if I have it above 1/4 throttle. Like if I stand on it to enter a road form a sidestreet, it flares real bad. If I manually shift through the gears I can get it not to flare.
If I start in 2nd gear it still flares, but does not when I manually shift to third.

Mxfrank:
Not sure what you mean by ruined...
My vacuum pump works. I am getting vacuum to the transmission via the vcv with the green reducer. The vent is coming off the bottom of the vcv.
My only other line goes to the shutoff switch on the pump via the keyed ignition. Where else do I need vacuum if I have eliminated the locks and climate control?
I have not seen any sort of blue amplifier.