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Transmission fluid level is very confusing.

6K views 7 replies 4 participants last post by  JacobB. 
#1 · (Edited)
Hello, on my 2.3 when I take out my transmission dipstick in the morning in my garage (level surface) after the car has been sitting all night, the level shows way high on the dipstick, almost to the first two bends. Then, if I wipe it off and put it back and and take it out again, it goes to just above the max fill line.

If I take it out after a good 25 minute drive, engine and transmission warm with engine running, wipe it off, put it back in and take it out again the level shows about halfway below the minimum fill line!! If I shut the engine off and repeat this process it goes just over the max fill line.

I really do not understand this, the picture posted is kind of hard to see but it is when the engine is running warm after a good drive. Please could anyone give me some closure on this? I am about to drain it all out and put some new stuff in because I really do not understand this thing.
 

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#2 ·
Don't try and understand the weird and wonderful ways of the Mercedes transmission dip stick!

Seriously though the only reliable way to check the level of the transmission oil is to follow the advice in the owner's hand book.

You need to check the oil with the car on a level surface

You need to do this when the transmission oil is at operating temperature

You need to do this with the engine running (because the front pump sucks a lot of oil out of the pan and changes the level on the dip stick)

You need to remove the dip stick - wipe it clean - shove it back in and then see where the level is




On a 722.4 transmission you can also consider the advice of the hand book and make a guestimate of the higher level on the dip stick with the engine off...
 
#3 ·
Thank you, but that is what I did, level surface, engine and transmission fully warmed up, car running, and I take it out wipe it and stick it back in and take it out again. It's just that I don't know if it is low or overfilled because when it's cold it appears way overfilled and when it's running it appears halfway below the minimum fill line under filled I forgot to mention, it was like that before when I first checked it, I added a whole quart of the correct fluid type, and the level is still in the same place when I check it!!! This car is so confusing!
 
#5 ·
Yes! I did not notice hardly a change at all, the quart was added about 5 days ago and the level is in the same place. I know I am adding it to the transmission, the dipstick with the red top to it and black clip under it. And I'm adding it to the same place where the dipstick was removed. The thing that stumps me is that it appears way overfilled when I first pull the dipstick out when the car has sat overnight and that when I put it back in and take it out again it goes down to just above the max line. But when the engine and transmission are hot, it appears way under filled!!!

Thank you, the hood pad is not original, I bought it from Mercedes and installed it almost a year ago. The old one was crumbling, every time is opened the hood I would find new chunks of it in between wires and in everything, the engine was a mess because of it.
 
#6 ·
Cold level of ATF means nothing. In other words, nothing.

Stretch explained how to correctly check the fluid level, just like the manual says.

If you added a quart of AFT to a warm operating temperature transmission with the engine idling and the fluid level did not change from below minimum level, then either the fluid level is indeed low or you can't see the fluid level correctly.

Consider having some other knowledgeable person check the warm operating temp with engine idling fluid level, or drain the fluid (both pan and torque converter), change the filter, and fill with fresh fluid carefully measuring as you go.
 
#7 ·
Right and I know that, but I just don't get why, isn't there fluid expansion when the transmission is warm so wouldn't you figure that there would be a higher level showing up on the dipstick when the engine is warm, not cold?

I have a mechanic who does this but he is out because he was injured, he has other workers but I trust him the most. I have another friend who might be willing to take a look at it for me.
 
#8 ·
I replaced the fluid in the transmission. Drained the converter, and pan. Out came about 5 quarts maybe a bit less.

I added 4 quarts, started the car, and shifted through P-R-N-D with a pause in between, then added the remaining two to make it six quarts. Car shifts a bit smoother now, but I don't notice too much change.


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