Jones1104

Car won’t move. Replaced torque converter and both sensors on the TCM. I’m afraid the transmission needs replaced. Any help is appreciated.

CaliBenzDriver

Car is not moving at all.

You have couple interesting faults with TCM, ESP, R-SAM including some CANbus disruption.

Can you feel gear changing between P - R - D... yes?

Research keyword "TCM CONDUCTOR PLATE".
You can get your part rebuilt to prevent unnecessary coding.
🤞

Jones1104

I replaced two sensors on the conductor plate already. It cleared those trouble codes and they haven’t returned since

CaliBenzDriver

You have fixed and cleared faults successfully

PRND Test ??

latest scan messages

Jones1104

The latest scans are posted. You can feel it engage the gear when you shift, but there’s no output shaft speed. Fluid level is correct, I followed the WIS step by step.

CaliBenzDriver

Great! Now go read TCM live data to see that conductir plate communicates and shaft speeds register after sensor fix.

Jones1104

I’m not sure what else I need to look at to ensure there is communication.

CaliBenzDriver

disconnected rpm: TC stalled
this is what's keeping your car put!

How to remediate that: not sure if it's pump, valve or converter related... but that's tranny internal.

Conveter needs enough oil pressure to work well.

Shops usually through a rebuilt kit at these jobs with seals, clutch frictions/steels plates and a rebuilt converter.

The ATF pump sends pressure to converter through valve body - - TC is not getting enough pressure...

Jones1104

I just put a “new” converter in, so that shouldn’t need done again…? Suggestions for a rebuild kit? Or any other suggestions?

CaliBenzDriver

Great then your almost there

​​​​​Did you have the same problem BEFORE dealing with the conductor plate sensors ??


A Xentry reader would expose more tranny data to help diagnose this issue. Now its a bit of hit'n miss unfortunately.

We now know TC is stalled - You just need to figure where pressure has a chance to get lost or go missing due to valve body...
🤞

Jones1104

My son was driving the car when it stopped moving. I’m not exactly sure what happened, but he said he tried to pull off from a stop sign and it bogged down and then quit accelerating. The car ran fine until that point, with the occasional hesitant jerk shifting into 2nd. I initially got the code for the speed sensor, so after researching I found the sensor on the TCM needed replaced. I did that, and when I put it back together I got the code for the other sensor. So both the 8n1 and 8n2 have been replaced.
I then got the 0894 code for slipping gears and upon further research, found it ways most likely the torque converter. So I bought and installed a known working unit with 68k miles on it.
This is everything I’ve done to the car since it quit running. I have a Launch X431 fit scanner and I’m not 100% sure of its capabilities. I don’t have access to a xentry or star unfortunately, so I can’t find out more in depth analysis to pinpoint where the pressure is being lost.
I apologize for not giving background from the start, but I’ve posted huge explanations to forums before and never got a response.

CaliBenzDriver

I see... what is best to do from here?

This sounds like a 5¢ O-ring in the ATF pump that sucking air through a 5¢ hardened O-ring.
Bevause of that converter is filling up with air filled oil foam that prevents filling up oil to pressurize converter.


Newish TC is hardly spining.
This has nothing to do with valve body solenoid and worned out clutches and everything with oil pump.
It's located right up front behind converter. High heat cooks undersized seals.


At that stage consider throwing a set of gaskets at it. Up to you to stop at the pressure pump without dealing with shafts.
If you research into that condition, you may find people who located exactly the built-in weakness that got you stuck.
🤞

Jones1104

I’ve seen a few videos showing that the bell housing has to be taken off and the clutch packs removed to access the oil pump. I haven’t looked at the WIS yet to see exactly how to replace/ service the pump. Any advice or instruction as to how to do it?
Is it worth tearing it all apart to simply replace the seals? Or should I get a new or refurbished pump?

CaliBenzDriver

I am not a transmission guy... professionals throw part kits at these gear boxes because labor to remove/install tranny warrants doing so once only. I admire what rehearsed miracles tranny experts do with thousands of parts assembled with precision like Swiss watches.

I know there is some sort of pressure regulator after ATF pressure pump. I'd focuss ont these early parts to cause air infestion/pressure loss and not much to do with valve body or cluch packs...

I could be entirely wrong too, unlikely just trying to help you save $5,000 USD and your car from the crusher.
🤞

Jones1104

I understand. I appreciate your help and I’ll let you know what happens when I get it done!

Jones1104

If I can find a transmission from a donor vehicle, what is the ECU swapping compatibility? Can I put an e320 ecu in my e350?

CaliBenzDriver

Nop, very unlikely - These 3.2 engines vs. 3.5 are vaguely related engines with different generation of ECU. I don't think this change can code in.

The MB computers architecture is like a GIANT PUZZLE. Every module fits in to interface through a gateway that feeds network data all around.

The main three modules are engine, tranny, brakes - CAN-Bus networking protocols were developed by Bosch... consequently brakes were given a central role to control wheels with firmware logic.

Jones1104

I’ve got the turbine speed and engine speed matching, but there’s still no movement

CaliBenzDriver

is it really shifting from P into D??

Jones1104

Yes, the target gear and actual gear are the same when I shift

CaliBenzDriver

You've got to try and use the scanner to guess what is not happening when you shift from N to D.

You can't trust wet-finger...
Let's guess one of the solenoid is not sending pressure to shift clutch pressure.
-- Do you see shift happening?

-- Car scan shows "No errors" about TCU Communications, right?

Jones1104

That’s right, no codes for the tcu. I can get under it and verify the shift is happening visually

CaliBenzDriver

Can your Launch X431 scanner read live data from modules and TCU in particular, yes?

This will show you status, conditions, pressure, shifts...
one of which should clue you with unexpected value.

These German cars literally are computers on wheels - Here you need to diagnose tranny computer... it will help diagnose what is wrong then we can fix what that is. It has no live fault to tip us so let's help ourselves to live data then
✌️

Jones1104

It will show which solenoid is assigned to which gear but it won’t allow me to see if it’s operating or not. It will really only show shaft output shaft speed, engine rpm, engine torque, clutch lockup open or closed, actual and target gears and a few other things I can’t think of right this second. But if you can tell me what it is we need to see exactly, I can get back and let you know

CaliBenzDriver

right now Id say 90% chance something is wrong with your conductor plate.

It sounds like your scanner is limiting progress... you can go the way you see fit:

1. replace conductor
2. get conductor repaired/recertified/tested
3. get Xentry scanner to access 100% of tranny help.

It's little bit of a bind:
-- Troubleshooting with a Xentry scanner would likely point to conductor issue.
-- You are going yo need Xentry for tranny adaptation