jthomas1231

Hello,

Car is a 2008 E350 RWD, 722.9 Transmission. I just replaced the front transmission pump due to a noisy front pump bearing. New filter installed. I used Mercedes STAR service manual CD when removing and re-installing the transmission (everything torqued appropriately). When I started the car, noisy bearing is fixed, but now car won't go into gear. In all gears, nothing happens, seems like a potential software or valve-body issue?

Here is the troubleshooting I did:
Ground wire OK
Electrical Connector Seated OK
Shift linkage works and changes transmission position with shifter OK
Hood & trunk closed OK
All underhood, front driver's, and trunk fuses OK (UPDATED)
Brake lights work when pressing brake pedal OK (UPDATED)
Cannot shift out of Park unless brake depressed OK (UPDATED)

I did swap the battery for a new AGM battery as the old one failed a CCA load test. Car starts fine, lights work, everything works, and even got transmission up to 40C as required in Mercedes manual for pan with incline. Used 10L of Shell ATF 134 (has MB 236.14 approval). 6L were added to pan through adapter before starting engine, and 4L were added after engine was started while in Park. It was when I put it into reverse to cycle through the gears that I noticed the reverse lights weren't turning on and neither was the display changing from "P" for Park. Turned off car and restarted x2 and same issue.

Is there any type of anti-theft or recoding that has to be done when the electrical connector for the transmission is disconnected? The only thing the MB manual (WIS) says is "Read out fault memory with STAR DIAGNOSIS and erase if necessary" and then "Perform transmission adaptation (required if transmission is changed or repaired)". I don't have a STAR system, but do have an OBDII code reader, I haven't pulled codes yet as it is 1AM now.

I haven't yet drained the excess fluid from the pan as required by Mercedes because it isn't even sensing it is changing gears.

UPDATE: I am going to leave the negative battery terminal disconnected overnight to try and see if that resets the TCU. Reading other posts it may be something that simple. I'll try and read TCU and ECU codes tomorrow.

Thanks in advance,

Jake

cmriv

is your torque converter installed all the way? Did you hear the "thump"? And if you only did mechanical repairs then you shouldn't have any "electrical" issues-which is what you sound like you have....

jthomas1231

Thanks for the reply.

I believe the TC is seated properly, it went all the way in, two stages - had to twist and wiggle for it to get seated and it still stuck out of bellhousing, but it was like that when I removed it, as the front of the TC has a nub that rests inside the flexplate of the engine.

Today I reconnected the battery hoping any capacitors would discharge overnight, but had the same symptoms as yesterday. Tomorrow I have a TCU capable scanner coming in the mail, so hopefully it is just a matter of clearing any transmission error codes.

I did connect a basic OBD-II scanner today and no ECU codes were pending or stored.

So if it isn't a TCU code, am I looking at valve body, shifter? Is it possible to break any plastic inside the shifter which senses the different positions? I read for the older E-class, there was a problem with that, but it was mainly when the car was stuck in Park. I don't have any trouble moving the shifter and it only will move out of Park if the brake is depressed.

jthomas1231

So the scanner came in today capable of clearing the Transmission Control Module. I read the codes and got a P2805, the description from the scanner is as follows:

(164/216/221/251) The signals from the selection range sensor are implausible in comparison with the signals from the intelligent servo module -OR -

The signals of the range selector sensor are implausible in comparison to the signals from the electronic selector lever module.

I Googled and searched Mercedes forums, but couldn't find any posts related to that code. The only thing I have found with symptoms related to mine are from an ML class that had a bad airbag sensor which wouldn't let the car go into gear. I checked the airbag module and had no faults.

I hooked up the new scanner and it read the Electronic Shift Module Selector and shows when the solenoid interlock is on, brake pedal depressed, what gear it is in, etc. The only other thing left is a bad TCM or a bad selection range sensor inside the transmission. I think any valve body issue requires re-programming by the dealer - although I can get access to a MaxiDAS system.

I may remove the pan to see if the selector pawl (rooster tail) is seated correctly, even though I double-checked it while re-installing the valve body and before torquing the new aluminum valve body bolts on.

I didn't think twice of it, but when I was removing the valve body to change the pump, the electrical connection had to be pried loose as in the manual. When I pried it, the transmission was in a vertical orientation sitting on my metal bench (with a hole for the output shaft in the tabletop) and the valve body flopped out, falling into the pan. I hope that didn't ruin the TCM or anything in the valve body.

Can a MaxiDAS reprogram a new or used valve body? Flash the TCM?

Reading online, known 722.9/722.6 valve body issues seem to be related to shifting while moving, not really to shifting out of park and nothing happening.

Any suggestions or ideas are always appreciated.

Thanks,
-Jake

konigstiger

“Suggestions”, check f46 @ front SAM (for the hell of it) and consider, control module selection range sensor (y3/8s1) may have been damaged or needs to be relearned-in using MB DAS.

cmriv

AH you are on to something....valve body lever may not be installed correctly.... let us know!

jthomas1231

UPDATE:

Yesterday I dropped the pan and discovered I had correctly installed the metal parking pawl (rooster tail) into the valve body spring, but the plastic range selector sensor was not hooked onto the parking pawl. The part number was y3/8s1 as suggested by konigstiger and cmriv. It was immediately apparent that this was the issue, it should have been a super easy fix.........

See this YouTube video (7 minutes, 35 seconds in) for proper installation of parking pawl and sensor (although his hand does obscure it, the range selector sensor appears yellow/orange in lower left hand corner of screen):
To remedy this, I loosened the valve body bolts enough to slide the plastic sensor into position, but in doing so, the plastic broke as the spring was still exerting force onto the valve body and the plastic rod was kinked and seized inside the sensor bore. I didn't remove the valve body because I was being lazy as it isn't as comfortable to install it on a lift overhead as it is on the benchtop.

After cracking the rod's hook, I tried to epoxy it and used some copper wire drilled and tied into the plastic, but that repair didn't work after I installed it again in the vehicle. The epoxy repair failed and the copper wire was holding it all together, albeit out of adjustment enough for the sensor to be reading Reverse when the Shifter was in Neutral.

I ended up sourcing a used replacement "rod" through a transmission shop and will have it shortly. Apparently, it is a common issue - the plastic rods become brittle with age and if you aren't careful when reinstalling the valve body, you can crack it. I didn't even realize the sensor was there as my transmission experience is with rebuilding older domestic transmissions.

Thanks for all the replies,

I'll post photos later for others that may have the same issue in the future. I'll be doing a DIY transmission front pump replacement thread and I'll include these embarrassing mistakes in there as well.

-Jake

P.S. If you watch the YouTube video, he says to torque to 90 in-lbs, that is INCORRECT, you'll break the aluminum bolt like that - ask me how I know. The correct torque is 7 Nm/62 in-lbs. Mine didn't have any washers - they were just a pan-head aluminum torx bolt. The valve body bolts are M6 x 33mm and part number is 0049907512.