Transmission Oil Change
Thanks in advance.
KRis
KRis
Correct, the dipstick is to check the fluid to make sure it's not too low or too full. Both can damage the tranny. Without the dipstick you're just left guessing and you don't want to do that. It's not a simple change because some fluid may still be stuck in the transmission bell housing.
KRis
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Oh..I also found you a dipstick for 15 bucks on Ebay: http://www.ebay.com/itm/Mercedes-Benz-722-6-Transmission-Fluid-Dipstick-Repair-Tool-1220mm-140589152100-/281220638218?pt=Motors_Automotive_Tools&hash=item417a0e660a&vxp=mtr
Greg




When new threads begin, on topics previously covered, all the added/fragmented search results just makes it much more difficult to find the needed information.
Considering all involved (e.g. purchasing all the required materials/parts, have access to a lift etc.), this is service best left to a dealer and/or independent mechanic.
There is also an electrical connector, a.k.a. as the pilot bushing, the old design has a high frequency of leaking and it would cost little more to replace with the new design, during the oil service.
All considered, this was a service I choose to have the dealer perform for $325 (including the pilot bushing).
The seal that Serndipity is referring to costs less than $5, so you may want to install the upgraded part.
Lastly, that PDF repeatedly refers to heating up the fluid, then it talks about checking the fluid temperature before topping it off. That's because the fluid expands when it gets hot. Hot fluid reads higher on the dipstick than cold fluid. Thats important because the WIS says if the trans is overfilled, damage will occur. You may want to use a pyrometer to check the fluid temperature.




Normally, the entire connector is changed - not just the O ring. However, it is awkward to reach, unless the car is raised on a lift.
It is not expensive (e.g. dealer supplied part was $31.50 and was same part number as that in the .pdf).
I've heard there is a way to drain it by disconnecting a cooling line and having a friend turn the car on and off...I thought I had a good instructional on it buried somewhere from my research days but cant seem to find it...
KRis








If left unattended, the ill effects are not only loss of transmission fluid (e.g. no dip stick to check) but, fluid wicking up the cable and damaging sensitive electronics that are the brains of it's operation .
Mechanically, the 722.6 transmission is pretty bullet proof but, that is only a small part of the story.
After many years of reading this board regarding transmission failures (e.g. search 'limp mode'), the vast majority of issues have been electrical in nature.
Specifically:
1. Although the transmission fluid was initially marketed as life time fill/service, MB has since discovered otherwise and now recommends it be replaced every 39K miles. The issue was failure of the conductor plate module, which is located inside the transmission.
2. In addition, the transmission control is based on a micro-processor unit/assembly that can be damaged by the aforementioned cable wicking. It has been a very common problem but, fortunately a fairly inexpensive and redesigned pilot bushing has been made available, to prevent this problem.
3. Lastly, a liquid spill in the sifter area, usually causes a control module located underneath, to fail.
The required labor and parts to diagnose and repair any of the above failures are not inexpensive (e.g. typically approaching the entire value of a 10 - 15 year old W208, W210 etc.).
PS: I recently replaced the transmission fluid, filter and pilot bushing on my 2001 CLK Cabrio and praying that my coffee habit doesn't wind up in the shifter module..
Last edited by Serndipity; Mar 26, 2014 at 12:09 AM.



