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05 E320 CDI w/ 4 Zone Climate Control, Panaromic Roof, Parktronics. MB SDS equipped.
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Discussion Starter #1 (Edited)
Someone at another forum came up with a conclusion/solution. It has to do with the mapping inside the TCM controlling the TC lockup. I too feel it is a software issue that MB never wants to address. It is meant to improve fuel economy due to high pressure from peers. 2005-2006 E320 has a new TCM module called EGS52. However, it makes shifting very erratic.

Doktor A RSN Fix REVEALED!!!! - Sprinter-Forum

There is a fix for Sprinter CDI. Sprinter CDI is using 722.6 transmission as well. There is a very high chance that it can be applied to E320.
 

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05 E320 CDI w/ 4 Zone Climate Control, Panaromic Roof, Parktronics. MB SDS equipped.
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Discussion Starter #2
However, I have read a guy in Poland having some tugging shifts when engine is cold. He replaced the TCC PWN Solenoid Valve. How hard is it to replace it in the valve body? Can someone comment? That could be the solution to people who complains about the shuttering shifts.
 

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I had a problem with shudder on my w220 s320cdi 2003.

This seems to be a common problem with this age of car at about 100K miles.

I believe in around 2001 mercedes changed the lockup regime where it engaged in 3, 4 and 5 at low revs. I think in later models it locks in all forward gears.

This results in a faster wear in the clutch pack in the torque converter eventually causing a judder as you would get in a manual car with a worn clutch.

Also the valve body can wear aswell. The lubrication pressure valve bore wears resulting in poor lockup clutch pressure.

http://www.automaticchoice.com/Catalogue/m140-va30.pdf

I have changed my torque converter and had the valve body rebored and it has made it much better. There is still a slight increased vibration when the lockup engages but that is to be expected as the damping affect of the the fluid coupling is lost.

Before I carried out this work I tried cleaning the valve body and replacing the lockup solenoid (quite straight forward) but it made no difference.

One other thing to check for is glycol in the ATF as this can give similar symptoms.

Adam
 

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05 E320 CDI w/ 4 Zone Climate Control, Panaromic Roof, Parktronics. MB SDS equipped.
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Discussion Starter #7
Nice. I have read that people often report replacing the valve body fixes the juddering TCC lock up problem. I am thinking changing the TCC PWM solenoid valve will be worth to try as a cheaper fix 1st. All new valve body will get the new solenoid valves. I think one should also clean the screening shield on the TCC lock up passage too. Also, I think the speed/rpm sensors should be inspected for damage.
 

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How much is that solenoid valve and how hard is it to replace it? I have exact same problems like everyone else. When car is cold there is lots of bucking, juddering and what not...once the car warms up shifting is almost perfect. Tried replacing ATF (complete flush), didn't really help that much.

Why don't you try Doktor A's (or whatever) fix? It's just $50
 

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Discussion Starter #9
the solenoid is only around 35 dollars or so. DARF fix is more for people having permanent Rumble Strip Noise problem. I think our problem or at least my problem are that the TCC lock-up and release are delayed especially when cold. There is around 1 second delay I can feel it. More noticeable when you put the tranny in Gear 2, gas and let off the gas pedal. Tachometer will drop to 700 rpm and then you feel the TCC release. I am suspecting the PWM solenoid is acting up. Remember that it is NOT just an on off switch. Its extension or contraction are depending on some PWM signals. My feeling tells me that it is very prone to missing accuracy over time.

Now back to steps in changing the valve out. The valve is on the top side of the valve body covering by 1 plastic shield. The tranny pan will need to be dropped and wiring connector will need to be turned and unplugged. I think there the work is too hard except jacking up the car and getting under it. The pan is almost in the center of the car.

Again, DARF will require some hole drilling which I really don't feel too comfortable to do.
 

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Discussion Starter #12
Rostra Transmission | PWM soleniods: failure due to wear

There are more readings regarding the PWM properties due to heat and wear. I am hoping the starting of this thread can pool some smart brains together to come up with a proper diagnoses of the wicked erratic TCC behavior.
 

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Discussion Starter #13
Thesis: PWM Solenoid OHM increases as temperate goes up. TCU does its adaptation only when temperate is up at operational temperature. Solenoid OHM increases as it ages with respect to temperature as well. TCU adjusts itself accordingly. However, the adjustment parameter is not suitable in cold temperature. ie, TCU applies too much duty cycle to the PWM solenoid when cold.

This is theory to be proven. However, i am not capable of using a data logger to plug into the TCC PWM solenoid circuit.
 

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Discussion Starter #18
I did some study on the valve body. I finally understand what DARF fix is. It is small relief hold you drive on the side end plate in the area where TCC regulating valve meets. You try to drill a small hole at the dead center of that area like so in the attached picture.
 

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I did the DARF mod this morning to a 2004 E500 with a shudder. Good news is the shudder went away, bad news is some of the gears went away too. Almost like limp home mode. Don't do it. I have to take it apart and plug the hole now.
 
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