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#1
09-30-2008, 07:21 PM
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722.6 Erratic Shifting Problems Solved
My 1998 E320 currently has 155K miles. Last year I had the car in the dealership to have new spring perches installed. While the car was in the shop (first time since I owned the car at 58K miles) they told me that the trans seal was leaking. I authorized the work since I was aware of this problem. When I picked up the car the invoice stated that they added transfluid. When I go home I checked the trans fluid level and it was low so I brought it back to the proper level.
Prior to this the car would have it's moments when shifting. When I punched it it would slam into gear. When I would accelerate moderate to heavy and maintain the gas peddle the car would go into neutral for a second as it was shifting from 3rd to 4th gear. When I didn't come to a complete stop and started to accelerate the car would jerk forward. Other then the above erratic problems the car shifted fine. After researching this problem on the MercedesShop forum I read posts that suggested that the trans connector could have taken in some oil. I assumed that this was the connector at the transmission end but another thread pointed to the connector at the TCM. I figured that it was highly unlikely that the trans fluid would work it's way from the transmission to the TCM. After removing the connector yesterday I was proven wrong. Below is a few pictures showing the trans fluid on the connectors: http://www.peachparts.com/shopforum/attachments/tech-help/59610d1222816207-722-6-erratic-shifting-problems-solved-img_0008.jpg http://www.peachparts.com/shopforum/attachments/tech-help/59611d1222816279-722-6-erratic-shifting-problems-solved-img_0009.jpg As I started cleaning the connectors I noticed that trans fluid was leaking out of the TCM as I inverted it. So I popped the circuit board out of the plastic housing and here is what I found: http://www.peachparts.com/shopforum/attachments/tech-help/59612d1222816451-722-6-erratic-shifting-problems-solved-img_0010.jpg So much for "sealed for life". There must have been over 2 tablespoons of trans fluid in there. After cleaning up the circuit board and connectors the board looks like new again: http://www.peachparts.com/shopforum/attachments/tech-help/59613d1222816579-722-6-erratic-shifting-problems-solved-img_0011.jpg I ended up cleaning up the board and connectors with brake disk cleaner. It is non-flammable, safe on plastic, cuts through oil and evaporates quickly. After driving my car to work today, the transmission shifts normally again thanks to all you contributed to the various posts about the trans fluid on the TCM connector.
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Ray 1998 Mercedes E320, 200K Miles 2001 Acura 3.2TL, 178K Miles 1992 Chevy Astro, 205K Miles 
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#2
09-30-2008, 08:37 PM
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Quote:
__________________
To see my 129 parts for sale visit: John Roncallo
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#3
10-01-2008, 09:03 AM
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Quote:
Where is the TCM connector located ? I m doing the transmission service myself this weekend and i d like to check for atf leaks in there. Thank you Last edited by Dimitris; 10-01-2008 at 09:37 AM.
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#4
10-01-2008, 01:31 PM
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Quote:
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08 W251 R350 97 W210 E320 91 W124 300E 86 W126 560SEL 85 W126 380SE Silver 85 W126 380SE Cranberry 79 W123 250 78 W123 280E 75 W114 280
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#5
10-01-2008, 01:54 PM
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Tranny fluid doesn't just magically appear in the TCM - it's getting in from a leaking seal or o-ring on the transmission. That part needs to be fixed to stop the problem on a permanent basis.
Otherwise - great post - nice to have pictures so folks can see and not have to envision what the OP is talking about.
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#6
10-01-2008, 03:00 PM
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Are you saying that the trans fluid in the TCM effects its operation? I wouldn't think the electronics would know the difference.
__________________
1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine) 1988 F150 144,000 miles (leaks all the colors of the rainbow) Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra
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#7
10-01-2008, 06:51 PM
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The TCM is located under the hood passenger side up towards the fire wall under the plastic box. It is the circuit board next to the relays. The board has two connectors, the connector towards the center of the car is the one that wicks the trans fluid, however you will need to remove both connectors to remove the TCM board.
wbrian63, You are correct that you need to stop the leak. I mentioned in my post that I had my trans seal replaced last year but the dealer didn't know to check the TCM for trans fluid. mpolli, Most electronic circuit boards are not designed to operate with any type of liquid on them. With the trans fluid inside the connector to the TCM could have acted like an insulator. If there was any graphite in the trans fluid then any it could have acted like a short between the contacts on the circuit board. Best to keep electronics clean and dry.
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Ray 1998 Mercedes E320, 200K Miles 2001 Acura 3.2TL, 178K Miles 1992 Chevy Astro, 205K Miles
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#8
10-01-2008, 07:51 PM
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Quote:
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Mit freundlichen Grüßen, Lynn 2000 SL500 Silver 2000 SL500 SOLD 1989 560SL SOLD 1988 560SL SOLD
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#9
10-01-2008, 09:56 PM
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Here is a photo of the TCM connector in relation to the other components in the compartment:
http://www.peachparts.com/shopforum/attachments/tech-help/59640d1222912496-722-6-erratic-shifting-problems-solved-img_0013.jpg It's the one with the blue shop rag wrapped around the wires.
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Ray 1998 Mercedes E320, 200K Miles 2001 Acura 3.2TL, 178K Miles 1992 Chevy Astro, 205K Miles
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