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Discussion Starter #1
Hi all,

I have recently changed the engine on my E320 1998 and in 2 months time the transmission failed, or so says the workshop: It doesn't shift from the 1st gear. It works for a few minutes then just nothing happens when put on D or R or any other gear. Before that I remember it had a weird behavior sometimes when shifting from 1 to 2 (the RPM jumps a bit before it shifts) and I have changed a speed sensor for it a while ago.

Now the guy at the workshop says since it stops working in a few minutes you just need a rebuild. Then "we'll see" about the TCM. He also did something that made me suspicious, he said on the phone I removed the tranny and checked it but when I visited the workshop without him knowing my car was outside, and when I asked about that he said he moved it. I'm no expert so is it possible to remove the transmission without removing the exhaust and supporting the engine? and can that happen without the car being lifted?
 

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Unless you misunderstood him, he's a liar and/or an idiot.

The TCM is in the electrical "box" under the hood. Indeed, even if you change the transmission you will still have problems until the trans codes are cleared from the TCM. And removing the transmission has nothing to do with the TCM.

Go retrieve your car and take it to someone who knows what they are doing.

And read through the 722.6xx FAQ thread so you gain an understanding of your transmission and what's going on.

Good luck.
 

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Discussion Starter #3
Thanks for your response. The TCM is one thing, he probably meant that this is a mechanical failure and after rebuilding he will get to clear codes and so on.

But is it true that jumping out of gear to neutral along with staying in the first gear is an indicator for a tranny failure?

Unless you misunderstood him, he's a liar and/or an idiot.

The TCM is in the electrical "box" under the hood. Indeed, even if you change the transmission you will still have problems until the trans codes are cleared from the TCM. And removing the transmission has nothing to do with the TCM.

Go retrieve your car and take it to someone who knows what they are doing.

And read through the 722.6xx FAQ thread so you gain an understanding of your transmission and what's going on.

Good luck.
 

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If it stays on 2nd gear, that is transmission limp mode. All well design by engineers to protect the car from future damages.
If you read this forum, the transmission failures are 99.9% electronic glitches, when I heard about only 1 confirmed mechanical failure.
It is quite common that shops are trying to charge few thousands dollars for transmission rebuild, when all it takes is replacing $160 electric plate.
Don't know how many choices of service you have, but those things are not that hard to DIY.
 

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Thanks for your response. The TCM is one thing, he probably meant that this is a mechanical failure and after rebuilding he will get to clear codes and so on.

But is it true that jumping out of gear to neutral along with staying in the first gear is an indicator for a tranny failure?
I still say he's an idiot, at least about these transmissions.

I don't know if the percentage is so high as Kajtek1 notes, but by far most problems related to limp mode and slipping gears and the like are electrical, be that a failing sensor on the conductor plate or fluid incursion to the TCM.

Some of this is REALLY easy to DIY, like check the TCM for fluid incursion, if found clean it out, replace the adapter/spacer at the transmission (this is outside of the transmission) and confirm the proper fluid level, then clear codes with proper MB-interface tool (not regular OBD-II). If that doesn't do it, then you drop the pan and valve body (this gets a little more involved) and replace the conductor plate. If you're a pre MY-2000 then replace the pressure regulator springs while you have the pan off. Fit a fresh filter when reinstalling and set the fluid level (236.10 spec fluid) and clear codes, then enjoy.

Your guy sounds like he works on cars generally, and actually knows nothing about MB specifically. Get it OUT of his shop. If you don't want to mess with it as DIY, then find an indie transmission shop or an MB indie that knows these boxes. Call or visit a few and talk to them about what is going on, and if they respond knowledgeably about about the TCM, conductor plate, etc. then you know they are not full of horse manure.

Hope that helps.
 

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Discussion Starter #7
I'll go see what he did today and I'm sure he will back his theory with whatever necessary. It's not hard for him to show a defective part here and there. But anyways, I'll try to take pictures and post them here.

Thank you guys for your support.
 

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Discussion Starter #8
I still say he's an idiot, at least about these transmissions.
I don't know if the percentage is so high as Kajtek1 notes, but by far most problems related to limp mode and slipping gears and the like are electrical, be that a failing sensor on the conductor plate or fluid incursion to the TCM.
You are absolutely right. When I went to check on him and asked him what was the problem he told me we're still working on your "gear box" and when I insisted to know what was exactly the problem he said some TCM component had to be replaced, When I went to see what was going on I've seen the conductor plate and he replaces some sensor/component there.

What I'm worried about now isn't exactly the bill but the possibility for him to make any thing stupid when reassembling my tranny and hence lowering its lifetime.

I have marked the part in the attached photo and I can get its part no. from EWB later. The lack of expert workshops in this part of the world is really sad
 

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The black thing that surrounds your circled area is the conductor plate and the sensors are built into it. If you need to replace a sensor, you replace the conductor plate.

But that still has nothing to do with the TCM, at least not directly. The harness connects the conductor plate to the TCM.

I think your shop is possibly competent, but they don't care about diagnosis when they can soak you for -- US$800?? -- to change parts. It's possible the mechanic uses TCM to mean conductor plate.

Just be sure they fit a new spacer/adapter and clean out the TCM before they clear codes.

Good luck.
 

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Discussion Starter #10
Yes that's pretty possible. He doesn't speak much English anyways. As far as I understand the TCM is located under the hood close to the passenger seat.

But anyways, the charges in the UAE are still lower than the US. He quoted a $1000 for the whole thing. I'm not sure now that he's rebuilding the tranny just to make sure or to charge me that amount.
 

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I have worked on literally thousands of your transmission.

Not one time have I ever replaced a TCM because it got transmission fluid in it. Only because the circuit board shorted out.


Since he has replaced the trans and it wont shift, you have to have the TCM recoded/resynced/rebooted, until that is done with a Mercedes scanner, your trans WILL not shift.



NO clear codes with Mercedes scanner = no shift.


Check Codes has also mentioned this.
 

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The point that most replies were trying to make is that a replacement conductor plate, and a thorough cleaning of the TCM board, and a new tranny adapter electrical pug (like USD$20 part) - your tranny might be good.

If the tranny is good, no need for e mechanical rebuild.

If the tranny needs to be rebuilt, you should have htme get a new conductor plate, TCM board cleaning, and new adapter plug anyway.

So you lose nothing trying those (3) things first, before going to rebuild the mechanicals to see if the problem is "electrical" rather than "mechanical".

Keep the faith !
 

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Discussion Starter #13
The point that most replies were trying to make is that a replacement conductor plate, and a thorough cleaning of the TCM board, and a new tranny adapter electrical pug (like USD$20 part) - your tranny might be good.

If the tranny is good, no need for e mechanical rebuild.

If the tranny needs to be rebuilt, you should have htme get a new conductor plate, TCM board cleaning, and new adapter plug anyway.

So you lose nothing trying those (3) things first, before going to rebuild the mechanicals to see if the problem is "electrical" rather than "mechanical".

Keep the faith !
I understand that very well. Unfortunately he didn't :)
 

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Discussion Starter #14 (Edited)
After rebuilding the transmission. The genius mechanic didn't check or OBD the car!! The tranny failed again after around 400 km of driving to find out that the radiator is full of oil. Changed the radiator and had the cooling system flushed. Went to him again to find out the ATF has water on it!! He just opened the oil pan, cleaned it and cleaned the filter, had the oil drained for like half an hour (I guess it should have been left over-night or at least for a few hours). Then put every thing back in and put like 7 quarts of ATF, and finally had the error reset.

The car was ok for a few hours, to finally have a few transmission slips (RPM gets high from 2-3 or 3-4) then it totally stopped. Now putting it on D is like N.

That happened around midnight in nowhere and around 140 km away from home, so imagine the pain, cost, and frustration.

Anyways, My 2 cent is: The conductor plate (which he did not clean) is still have some water and it shorted some sensors or solenoids and caused a limb home mode again.

Could there be any different reason? Could my TCM be failing for example?
 

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Dropping the pan never got me more than 2.6 l of fluid. Even overnight dripping will not get much more. Where the 7 quarts go?
Your 1998 has converter plug. Drain everything well and refill.
 

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After rebuilding the transmission. The genius mechanic didn't check or OBD the car!! The tranny failed again after around 400 km of driving to find out that the radiator is full of oil. Changed the radiator and had the cooling system flushed. Went to him again to find out the ATF has water on it!! He just opened the oil pan, cleaned it and cleaned the filter, had the oil drained for like half an hour (I guess it should have been left over-night or at least for a few hours). Then put every thing back in and put like 7 quarts of ATF, and finally had the error reset.

The car was ok for a few hours, to finally have a few transmission slips (RPM gets high from 2-3 or 3-4) then it totally stopped. Now putting it on D is like N.

That happened around midnight in nowhere and around 140 km away from home, so imagine the pain, cost, and frustration.

Anyways, My 2 cent is: The conductor plate (which he did not clean) is still have some water and it shorted some sensors or solenoids and caused a limb home mode again.

Could there be any different reason? Could my TCM be failing for example?
This is VERY important. Is it "slamming" into drive and reverse?
 

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After rebuilding the transmission. The genius mechanic didn't check or OBD the car!! The tranny failed again after around 400 km of driving to find out that the radiator is full of oil. Changed the radiator and had the cooling system flushed. Went to him again to find out the ATF has water on it!! He just opened the oil pan, cleaned it and cleaned the filter, had the oil drained for like half an hour (I guess it should have been left over-night or at least for a few hours). Then put every thing back in and put like 7 quarts of ATF, and finally had the error reset.

The car was ok for a few hours, to finally have a few transmission slips (RPM gets high from 2-3 or 3-4) then it totally stopped. Now putting it on D is like N.

That happened around midnight in nowhere and around 140 km away from home, so imagine the pain, cost, and frustration.

Anyways, My 2 cent is: The conductor plate (which he did not clean) is still have some water and it shorted some sensors or solenoids and caused a limb home mode again.

Could there be any different reason? Could my TCM be failing for example?
The problem is that there is still water in the transmission.

Drain everything (cooling lines, torque converter, pan, pull the valve body and let it drain out too.

Then reassemble and fill with fresh ATF, then flush about 10L more fluid through through it.

Then reset the TCM...again.

All of this he should do at no charge, since he rebuilt a transmission that didn't need rebuilding, you obviously overpaid, and you have paid him to get educated about your transmission (something he is still lacking, anyway).

Anyways, My 2 cent is: your mechanic = idiot. ;)

Good luck; it's about time you had some.
 

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Discussion Starter #18
The problem is that there is still water in the transmission.

Drain everything (cooling lines, torque converter, pan, pull the valve body and let it drain out too.

Then reassemble and fill with fresh ATF, then flush about 10L more fluid through through it.

Then reset the TCM...again.

All of this he should do at no charge, since he rebuilt a transmission that didn't need rebuilding, you obviously overpaid, and you have paid him to get educated about your transmission (something he is still lacking, anyway).

Anyways, My 2 cent is: your mechanic = idiot. ;)

Good luck; it's about time you had some.
I completely agree with you Check Codes. He calls the conductor plate "TCM" and when I told him (after a long arguments and disputes) that he's wrong about that and many other things he got offended!!

He pulled the valve body (as far as I understand it's located in front of the pan. He actually manage to drop 7 quarts since he added the same amount after he cleaned up the pan and the filter and put every thing back in place.

I towed the car to him again today (a 50 miles trip) and I found out that it's leaking ATF (was draining at the towing crane). So that's another incompetent act of his men, Guess they didn't fix the pan or gasket properly.

Finally I have a couple of questions:

- If 7 quarts have been drained, is that all? If not, how to drain the cooling pipes?

- Does the conductor plate need to be taken away and cleaned?

- Can oil leak cause shift slips followed by no shift at all? I guess it can.
 

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Discussion Starter #19
This is VERY important. Is it "slamming" into drive and reverse?
I didn't fully get what you mean. But It doesn't automatically switch from d to r nor it jerks. The RPM just jumped from 2-3 then it totally died. My prev post has more info.

Thanks Mechanic
 

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You need to get more precise info on the service. It is possible that the pulled the plug on converter to drain 7 quarts and you don't know about it? Full capacity is 9 liters, but check it in the stickies.
Low ATF level will sure stop the transmission from working.
Per my experience -the top of conductor plate collects lot of solid dirt. If that wasn't clean before, it is not a big job if you have the conductor plate removed to get there and clean it very well as well.
 
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