Hi Everyone,

Thanks for all of your support in the past in resolving problems with my various mercedes.

About a year ago, I experienced the transmission in my 1998 E320 acting up by whining and slipping. After reading the forum, I found that the plug adapter from the transmission was contaminated with oil. I replaced the plug adapter and was surprised when I experienced the same symptoms a year later. I checked the plug adapter and sure enough it was coated with oil. I cleaned the plug and adapter and ordered a new adapter 2 months ago but did not get a chance to install it. A few days ago, the transmission started whining and slipping so I installed the new plug adapter. This time it did not cure the problem. After 10 minutes or so, when the transmission is at operating temperature, the symptoms start. I checked the TCU and it had oil in it. I cleaned it with contact cleaner and it does not seem to be dirty any more and I cleaned the plugs and wiring. This has not cured the problem. Should my next step be to swap the TCU?

Thanks in advance for your help.

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1988 420 SEL
1991 420 SEL with 560 motor
1993 Miata

How many miles are on it?

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Jim

The car has approximately 145,000 miles on it.

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1988 420 SEL
1991 420 SEL with 560 motor
1993 Miata

Im no transmission expert but cured my 94 E320 of slipping (mostly in reverse gear) by adding blue devil stop leak. Now this was a barn beauty..the car had been sitting and full of mice with low trans fluid levels..not being driven. (owner lost her license) and it had issues from sitting..I added and changed fluid and fooled around with additives and eventually its 100%. (also changed the Vacuum modulator valve, which began leaking and created a huge smoke issue!) Now 200K miles and going great.

Good luck Dave..

My guess is ATF in the transmission module caused module level codes that need to be reset. Check your private messages.

Sixto
98 E320s sedan and wagon

x2, if the connector and TCU are clean, and the fluid level is correct, I would scan the TCU for codes. Clear the codes and also clear the adaptations.

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1998 E300 turbodiesel

America's Rights and Freedoms Are Not The Enemy!

These symptoms also point to split open speed sensors - they start to act up when the ATF is hot. Check the deeper level codes and see what is wrong. You will need to read the ATSG manual to understand how this transmission works and what the codes mean.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

I met with davestx. Codes 147 and 151 returned after clearing. He's working on next steps.

Sixto
98 E320s sedan and wagon