FreddyB

Hello all, apologies for the long read.

I have a 2005 E500 4Matic Wagon with the 722.6 transmission that is giving me some issues. I have been driving the car for about an hour before the issues occurred, parking the car for about another hour or so, then coming back to the car to drive again. When shifting the car into drive, there was a rough jerk of the car unlike the usual soft gear engage feeling even in Sport mode. Driving away reveled the car was not shifting out of 1st gear and could not be manually shifted out of 1st. I pulled over, turned the car off and had the key out for about 2 minuets, then turned the car back on to drive again. Shifting into drive still had the aggressive jerk and this time the gear indication on the dash did not change out of Park. I then drove the car for about 30 more seconds to move it into a safer area when the throttle was unresponsive for a few seconds, then came back to the motor free revving in gear, with the transmission not going into any gear. Turning the car off and then back on did nothing to the gear indication on the dash, and the car was not going into reverse or drive. Had the car towed back home and I started looking into what I could.

Checked the transmission fluid level and condition once the car was back home, level was good and no noticeable looks or smells. I have owned the car for a while, and have just over 160,000 miles on it, but I service the fluids very frequently due to the higher mileage. I have flushed the transmission fluid every 25,000 miles, and was about to do a full flush once again before going on a long road trip. Dropping the transmission pan showed no large particles or fragments, no abnormal build up in the fluid or on the pan magnet. Just normal deposits from high miles. Cutting open the filter showed no large fragments or concerns either. The conductor plate and connector have not been replaced, and disconnecting the main transmission connector showed quite a bit of transmission fluid on the connector. I removed the harness loom to inspect for wicking and inspected the TCM connection and found no transmission fluid at the TCM. I also removed the TCM from the case and found no fluid on the circuit board. I removed the valve body and disassembled it for cleaning and found no blocked passages or broken springs. I tested the solenoids and all functioned when powered. (tested out of the conductor plate) I purchased a new conductor plate and connector from FCP Euro and replaced the old units, keeping the original valve body and solenoids. I reassembled the transmission and used dielectric grease on the transmission connector and TCM connectors. I filled the transmission with about 3.5 liters and attempted to warm up the transmission to verify fluid level but the car still would not go into any gears, but this time with a new symptom where you could hear an audible clicking coming from the transmission solenoids, clicking about every half second and changing in rate as the shifter was moved to Reverse, Neutral, and Drive. This was not present before replacing the conductor plate and connector.
I had previously checked the TCM for codes and faults with an Autel MX808 and did not have any codes. Going through all the Drive systems the only code I was able to find was a P1856 "Selector lever position detection has failed". I ordered a new floor shifter unit and replaced the old one, which got rid of the code and fixed the gear indication not changing on the dash, but the transmission would still not shift into Reverse or Drive. I left the car battery disconnected for a night and reset all the transmission adaptations I could with the Autel unit and still no shifting.

I viewed live data attempting to located the issue, but have only noted the following:
I am able to communicate with all Drive modules and read live data (ECM, TCM, Floor Shifter Assembly, etc.)
Status of solenoid valve for the 1-2 or 4-5 shift would rapidly change back and forth from ON and OFF
Status of shift valves would rapidly change from 1-2 or 4-5 and 3-4 to 3-4
Target gear reading correct to the floor shifter, but Actual gear would be only be P when in Park and N for Reverse, Neutral, and Drive. (did not change with manual up / down shift)
When putting the car into Drive (1st gear), Actual gear would be N for about 60 seconds, then change to 1. (would change to 2 if in C mode), though Transmission output speed would still read 0rpm and wheels would not move with any throttle input
Emergency Running NO (transmission never went into limp mode)
When first starting the car, WP438 (speed sensor 2) would read, but WP439 (speed sensor 3) would show 0rpm, then after about 60 seconds would match rpm's with speed sensor 2. (idle about ~438rpm)
Transmission output speed would read 0rpm in all gears, P-N-R-D, manual gear up / down, and in S and C modes. (increasing engine rpm's did not effect output speed)
All other data I have attached screenshots of live data, and a video link to the solenoid clicking sound.

I feel I am mechanically inclined, and have a basic understanding of automatic transmissions from research and reading the 722.6 manual, but am no expert and am coming to a loss with this problem. Because of the solenoids clicking and changing in the data, I am leaning towards electrical problems, possibly with the TCM itself.
1. Are there any other tests I could preform to verify the condition of the TCM?
2. If the TCM is faulty, what would be the direction to go for replacing it?

I am not one to just throw parts at problems until its fixed, but I am running out if ideas. I will be away from the car for a while, and only have a week left to work on it before traveling, so money is not a limitation with this car and I need it fixed, or at least movable, as soon as possible.

Any help would be appreciated, and if any more info is needed please let me know.

Thank you.


Speed Sensor 2 3 After

Status of solenoid 1-2 or 4-5 Shift

ECU TCM Info

Speed Sensor 2 3 Before

TCM Front

TCM back

TCM PN

Status of shift valves 2

Status of shift valves 1