[joegrinds_247]

Hi Guys,

I have a 03 S500 4Matic, about 8 months ago I had the fluid change, it was overfilled so I had them drain out the excess. A month ago after checking the fluid, I found it was still overfilled by a quart which I drained out. I checked fluid level because car started driving stiff, as if I were towing something. The vehicle doesn't flow as freely as it used to, my mpg has decreased because of this. When I move my feet of accelerator, I can feel the car slowing down on it's own. There's also a humming noise for few seconds when D or R is selected. The fluid isn't burnt, I know its the tranny because I experienced this on another non mb vehicle before. Which I sold. Any ideas what I'm up against here?

 

[tony1963]

Whomever did the service was inexperienced. My suggestion is to start over. Order the following parts:

1.) 6 Qts MB Fluid
2.) Transmission Pan Gasket
3.) Transmission Filter
4.) Electrical Connector Seal
5.) Locking Tab for Fill Tube
6.) Correct dipstick with measure
7.) Conductor plate

If you're going to open this up again, change the conductor plate. Leave the transmission drip overnight and replace everything. Then, add back 4 qts of fluid, start vehicle. If it is not registering, add 1/2 qt until you see it registering.

Drive the car 1/2 hour to get fluid to 80 C or about 176 F. Then, check again. Add as appropriate.

I recommend driving the car for a week before your final check and you'll likely add all 6 quarts or very close.

No way to properly diagnose until all of this is behind you.

 

[joegrinds_247]

Thanks Tony for your reply. I'll order these items and have it serviced by a professional this time. Will do a follow up soon.

 

[atmsmshr]

Hi Guys,

I have a 03 S500 4Matic, about 8 months ago I had the fluid change, it was overfilled so I had them drain out the excess. A month ago after checking the fluid, I found it was still overfilled by a quart which I drained out. I checked fluid level because car started driving stiff, as if I were towing something. The vehicle doesn't flow as freely as it used to, my mpg has decreased because of this. When I move my feet of accelerator, I can feel the car slowing down on it's own. There's also a humming noise for few seconds when D or R is selected. The fluid isn't burnt, I know its the tranny because I experienced this on another non mb vehicle before. Which I sold. Any ideas what I'm up against here?

Joe,

Some questions just to make sure we don't steer you wrong.

Do you have a CEL or any pending codes?
Are you using a MB tranny dipstick to measure level, or a home made dipstick?
When measuring, is the engine coolant temp at 80 deg C, car in park, and engine running? (Trying to measure immediately after adding ATF may give a false high reading)
What type of filter was used during the pan drop?
What type of ATF (manufacturer and fluid spec) was used? (These cars originally came with 236.10 spec fluid, which is no longer widely available. Also, when I swapped over our three vehicles with 722.6 trans to new fluid, I either did a complete drain with those that had a torque converter plug, or a full flush on our S430 to avoid mixing 236.10 ATF with 236.12 ATF).

The fluid level on these transmissions is pretty finicky, so using the right ATF and getting the right level is critical to smooth shifting.

Mike

 

[unimoged]

What you describe as "humming noise" and slowing down, etc, indicate an issue with the transfer case clutches. Make sure your tire pressure is right on all 4 wheels. Regarding checking the fluid, I am assuming you are using the proper dipstick.

Also, take a look at the TCU connector and clean it since fluid might have migrated up the harness to the TCU pins.

Anyway, you are lucky since you have the 5 speed unit.

I am dealing with an S500 2004 with the 7 speed, code 2112. The 7 speed has the TCU in the conductor plate itself floating in the oil bath. I can't image what these idiotic grand masters of engineering in sindelfingen were thinking, to place a siemens TCU in the oil bath, what an a stupid idea.

Good luck with yours.