99 W163 Transmision Project

[93w124]

I inherited a 1999 ML320 with 130K miles last week with a transmission problem I hope to fix with DIY elbow grease in the next few weeks. The gearbox was never serviced since the vehicle was purchased. The 13-pin electronics connector on the gearbox is soaked with ATF and needs R+R. Shifting symptoms include locking up in 1st gear during harsh acceleration, sometimes slips to neutral from 4th gear when forced to climb uphill, and will not downshift to 3rd or 2nd from 4th when needed. Very unreliable improper shifting. Spent some time looking into some common 722.6 gearbox issues out there and found it may be one of these suspects:

1. R+R ATF and Filter (Gearbox Service and Correct ATF Level)
2. 13 pin electronics connector causing faulty signals to ETC due to ATF leak.
3. Possible damage with conductor plate/electronics kit in transmission.
4. Damaged Pressure Regulator Spring in Valve body.
5. Damaged ETC Module

I plan to DIY 1,2,3, and 4 with some online reference materials then have the fault codes erased to see if they make a difference. Took it to a local dealer to get the fault codes ($160.00 ouch!). Please share your thoughts. I appreciate any input. Thanks!

ETC- Electronic Transmission Control PIN 11
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52 The torque converter lock-up clutch causes impermissable closing.
65 Component N 15/3 (ETC [EGS] control unit) is faulty.
135 CAN Communication with the engine system is sporadically disturbed.
136 CAN Communication control unit instrument cluster is sporadically disturbed.
137 There is a sporadic fault in CAN communication with control module N78 (transfer case control module)
or the transfer case position is sporadically implausible.
146 The Transmission has sporadically an impermissable transmission ratio.
147 The gear is sporadically implausible or the transmission slips sporadically
148 The torque converter lock-up clutch causes a sporadic impermissible closing.

ME2-SFI - Motor Electronics 2 PIN 7
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P0700-105 Read out fault memory of control unit ETC
P0300-080 Misfiring Damages TWC
P0306-084 Misfiring of Cylinder 6 Damages TWC

ESP - Electronic Stability Program PIN 9
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C1012 Terminal 87 Overvoltage
C1022 Fault in CAN communication with control unit N3/10 (ME-SFI [ME] control unit).
C1032 Fault in CAN communication with control unit instrument cluster.
C1140-007 N49 (Steering angle sensor)
C1140-008 Component N49 (Steering angle sensor) is not initialized.
C1120 N64 (ESP yaw rate sensor)

BAS - Brake Assist PIN 9
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C1012 Voltage supply circuit 87 : Overvoltage
C1202 A7/7s1 (BAS release swtich) : Plausibility

AAM - All Activity Module PIN 12
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B1703-004 Transponder: error when writing programmable code.
B1858-002 Two-way radio signal: The programmed code is o.k. but the programmable code is not synchronized.
B1786-002 The CL signal contact Tailgate supplies implausible values. - FAULT during locking.
B1040-001 CAN bus: fault in communication: ETS
B1040-003 CAN bus: fault in communication: VG