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1999 Mercedes E320
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10 Posts
Discussion Starter #1
This is by far the strangest automatic issue I have ever had or seen. It's not cut and dry like a bad clutch pack, burned fluids, a bad TC, tired bands, a leaking valve body, or solenoids.

Before I describe the actual issues, I want to be completely clear. It is having several different sets of issues that will change on each startup. After the car is shut off and turned back on after any amount of time they will generally change. Sometimes there are no issues at all, sometimes it'll present one set of issues and I'll just shut it off, then it will move to an entirely different and unrelated set of issues with some, all, or none of the previous issues being there. The behavior will not change as long as it's on. If I'm having one set of issues I don't see more appear or any go away until the next time I start the car.

That being said, I have two common and consistent issues. The first is major shift flares. If I start the car and it flares the 1-2 or the 2-3 it will not go away or get worse the entire time I'm driving it, until I shut it off and restart the car where it may or may not flare at all or might flare on a different change. It never ever hesitates or flares on kickdown. It's not giving any symptoms of clutch pack failures, there is not any slipping once the car is in gear.

The second common issue is that, occasionally, the car will borderline leave me stranded. It will not shift or accelerate. If I floor it from a dead stop the engine will go to 3k RPM and nothing will happen. If I move down to 10-20% throttle it will slowly begin to accelerate and will not move out of the first gear even coming up on redline. If I shut the car down then restart it the issue goes away.

My bigger concern is that I'm getting zero transmission codes. No generic codes through the OBDII port and nothing through the 38pin. I tried to check it with an Autel MaxiSys Pro with a 38pin adapter, thinking my scanner might just not be compatible I brought it to an indy that I know has dedicated 38pin scanner and there were still zero codes. There are codes for everything else from the ABS system to the lighting, but no codes from the transmission computer.

Now, all of that being said, the transmission fluid is very old. It's closer to a brown/grey. I've confirmed that the coolant is not leaking into the transmission fluid or the other way around. The transmission computer and wires also had no fluid wicking up into them.

Any ideas? Obviously a fluid change is in order soon, but I don't have any other ideas just due to how inconsistent the issues are but how they don't change while I'm driving it.
 

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1999 E320, 2000 E320, 2003 E320 Wagon, 2005 C230K SS, 2010 Accord LX w Eibach & Koni FSD's
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3,177 Posts
Did you pull the transmission electrical connector plug out to see if there was fluid there? Mine was just starting to leak on my W203 and it caused hesitation and flaring problems.
 

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1999 Mercedes E320
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10 Posts
Discussion Starter #3
I'm going to be honest I'm feeling like kind of an idiot right now. I didn't think to check the inside of the connector on the transmission side. I'll definitely be doing that tomorrow.
 

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W163 and General M Gremlin
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3,749 Posts
I'm going to be honest I'm feeling like kind of an idiot right now. I didn't think to check the inside of the connector on the transmission side. I'll definitely be doing that tomorrow.
I would recommend you also check the other end too, at the TCU, potential wicking up the harness.
No codes doesnt necessarily mean it hasnt wicked up or in progress.
Have a can of electrical CC handy.

Keep us posted.
 

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2000 E320 (W210) Obsidian Black
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114 Posts
First thing I would do is change transmission fluid. You say it is very old and brown/grey. These transmission's respond well to fresh fluid. BTW, if the AT dipstick tube is capped with a red plastic cap the fluid probably has never been changed since it left the factory in '99.
 

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2000 E320 (W210) Obsidian Black
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114 Posts
Oops! Nasty possessive apstrophe in my comment above (transmission's - aaaargh!)
 

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1999 Mercedes E320
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10 Posts
Discussion Starter #7
I would recommend you also check the other end too, at the TCU, potential wicking up the harness.
No codes doesnt necessarily mean it hasnt wicked up or in progress.
Have a can of electrical CC handy.

Keep us posted.
I've already checked the transmission computer end, it was bone dry.

First thing I would do is change transmission fluid. You say it is very old and brown/grey. These transmission's respond well to fresh fluid. BTW, if the AT dipstick tube is capped with a red plastic cap the fluid probably has never been changed since it left the factory in '99.
Yeah, the fluid change is going to be soon when I do the center support bearing. The AT tube was capped with a black cap with black tab and already had the tab broken off of it when I went to check it. I know that at some point this car had been to a Mercedes dealership for a transmission overhaul but not by me or the last three owners in the last decade.

Also, to be fair, wouldn't the transmission be in possession of the fluid? If I had to take it to look at the sunset one last time, wouldn't it take it with it?
 

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Moderator
93 SL500, 95 SL320, 96 S320, 98 S500, 2002 E320 4Matic Wagon & A little 91 5.0 FORD Mustang
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8,136 Posts
Here is what I would do:

A) Order your self a 722.6 testing dipstick on Ebay for $10 to $20 bucks - Do not Micky-Mouse this with a coat-hanger/large cable tie/ etc... Or go buy the MB one $80-$100
B) Change your fluid(oil pan only) and filter. Use your favorite fluid, and you can use the low price Valvoline MAX-Life ATF from Walmart at $18/Gallon. It is in all my cars, and I rebuild tranies with it too.
C) let the car idle for 20 minutes to get the proper hot dipstick reading. If you get a check-engine to come on during the 20min idle you have a P04*(some kind of evap error-not related). The demons come out on 20-30min idles....
D) The "Will not shift or Accelerate" is catastrophic by nature, but it can be that you have NO shifter bushing(s)-They are missing or the urethane rubber has turn to marshmallows.... And.... Causing the transmission shift-arm not to index into its slot, so it is "in-between" shifts, and the transmission Mono-valve cannot send fluid to the appropriate valve galory, so fluid is halted from traveling.



E) car is still flairs? need to go in for two inspections..
F) Inspection #1, Broken regulation spring that occurs on all 90's 722.6's. Here is how to remove the valve body/conductor plate/regulation spring





G) Inspection #2, look at the conductor plate speed sensors for cracks-super important-bring out a magnifier


You see a crack here buy a new conductor plate, AND DO NOT buy the cheap ebay Chinese units. Buy from a reputable source, or a MB Dealer one....

H) You may still have some flair, but maybe not as violent, and you may need a overlap kit:


You got plenty of home work to do. You can recycle your fluid, and re use it. Remember to replace the circular connector in the first link in step F. Follow all the links and READ THEM !!!!!! tooo. Let the car idle to hot to get a excellent fluid reading-too low or too High fluid causes all kinds of wonky symptoms.Be patient. Let it idle. I do that for rebuilds it is a safe way to get a hot fluid reading. Ahh get your self a cheap torque from Harbor Freight(the small one) to tighten the circular connector to the valve body. Overtighen that bolt, and you bought your self a new conductor plate !!!

My guess you have a broken regulation spring...

Martin
 
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