A dumb question about ATF

[dling1234]

Hi,

I have a 87 300E with 145K in it. Why the correct level of ATF is so important? Why overflowing, if not too much, will cause problems with the tranny? I also noticed when checking the ATF level, the temperature of the ATF are important considerations and I'm now totally confused.

Let me put it this way, for a simple minded low-tech such as I am, what's the corret level of the ATF should be after about 10-15 min. of driving?

DL

[stevebfl]

No more than the top line on the stick. Look at both sides and use the lower reading.

If the level gets too high the rotating parts get into the pool of fluid and foam it up. When this happens the fluid often comes out the vent at the top and makes a mess. I have seen cars get so foamed up they would no longer drive. The clutches and bands will not apply under vapor pressure, they need real hydraulic pressure.

[dling1234]

Thank you for the quick advice. I've also called local Mecedes dealer and this is what they said:

Keep the car in the garage over night and start the car next morning and let it idle for 2-3 minutes. Check the ATF level and it should be 10 mm below the lower mark on th dipstick.

Pretty specific, isn't it? Any comments?

Again, thank you and many others who have responded to my other postings. This Forum is truely awesome!

DL

[stevebfl]

Those instructions won't fly. First of all just idling the trans will still be cold. I wouldn't want the level below the bottom mark even cold.

The difference between the bottom mark and the top mark is probably a pint or so.

[dling1234]

Thank you very much. I think what I'll do is to first check the ATF level when it is cold then check it again after it has been driven for 15-20 min. and check it again. I'll make sure the ATF level is between low and high marks. Is this a good approach?

By the way, the smear on the dipstick is not very clear at very hard to tell the right marks, any suggestions?

[stevebfl]

I find, especially when filling that one side of the stick must wick up fluid from the tube. It will look very high. The other side of the stick is what to read. It should be fairly clear.

[md21722]

Steve,

I was reading this thread and I believe the dealers advise is somewhat accurate as I've read it in the shop manuals or the owners manual. I don't have the computer technology readily available to scan in the information but I'd be interested in your comments if you did come across it.

Regards,

Since most of the cars which I have been able to afford over the years have been very thoroughly used by the time I bought them, I've often had to deal with some ATF leakage, as is the case on my current '85 300TD (333,357 miles). I have adopted the practice of getting the fluid level to the exactly correct level by the factory method and then parking each car in its usual place on our slightly sloping driveway and checking the level again with everything cold. I make an extra mark at the resulting level so that I can do a quick check in the morning anytime I feel insecure about the ATF level, which is often. I never add any, however, except after rechecking with it all at the proper temperature, car as level as possible, etc., etc..

[dling1234]

Hi, all:

Thank you all for the great advice. Let me ask another dumb question, why can I check the ATF level when the car is parked level and cooled off overnight? I assume all the ATF would be resting at the bottom of the tranny. Wouldn't it be more convenient and accurate to check it rather than when the engining is running and ATF are splashing around ( could be my imagination)? I'm still having hard time to read the dipstick it is still too confusing to me where the real level is.

DL

[Ali Al-Chalabi]

The dipstick is calibrated for the tranny in park with the engine running and tranny warm. Check it according to the advice given here for accurate results.

[jgl1]

M-B superceded the 722.3 - 722.5 transmission fluid dipsticks to a new style "Workshop" dipstick that has level markings for two distinct ATF temperatures (workshop ambient and operating temperature). Part number is 140 270 06 83; approx. $19 retail. Use of this dipstick can help eliminate confusion regarding proper ATF level when measurements are taken prior to reaching operating temperature.

[dling1234]

Hi, all:

Again, thank you all for offerring so many wonderful tips.

I may have found out my problems, my ATF might be too low that's why I had hard time in picking up the readings on the stick. Also, when I added the ATF I should have waited for the ATF to completed traveling down the tube before I checked it again. since the fluid was still at the side walls of the tube that could mess up the reading. When the engine was turned off the fluid level is at about 3/4" below the low mark but when the car is idling, hadly any fluid visible. That looked like the fluid level was too low, I hope not too much damage have done to the tranny. I'm gradually adding the fluid to the tranny as we speak.

If you think I'm doing the bad thing and might end up adding too much fluid, please warn me. Thanks.

DL

[dling1234]

Hi, all:

My tranny problems have been solved. My ATF level was "too low" and that's why I could not see the fluid level. I felt a little stupid, checking the fluid level really should be the first place, and easiest, to check. Since I spent $$$ and had the car thoroughly, so I thought, checked and serviced by a local mechanic I assumed he checked all fluid level including ATF. How wrong could that be?Once I slowly adding up the ATF I began to see the fluid level registered on the dipstick. I ended up adding about 2- 1/4 quarts of ATF to the tranny. Once the level is correct, all my tranny problems are gone. Now tha car runs smoothly.

Do you know if the extremely low ATF has already done some real damage to the tranny? By the way, how much ATF should the tranny take?

Thank you all for great tips and I certainly have learned a lot.

DL

[Peter Fearing]

News bulletin: Since '97, MB trans come with a perminate trans fluid. I have over 200K miles on my W202(C280) and have never tried to check the level or change the transmission fluid. To date the car operates perfectly, runs like new. Go figure.

Hi,
I was also quite ignorant regarding ATFs.

Mine is a 722.4 with a dipstick. The mechanic checks the fluid with the engine running, In Park and the engine quite warm.

I thought it was like checking engine oil wherein it can be done when the engine is shut down.

My car's mileage is in the 115,000 kms plus. The MB dealer says I should drain and change the fluid every 100,000 kms. I checked the fluid condition and it is still very clear. It says nothing about trans. fluid change or any service in the owners manual.

BTW. What ATF are you using for the car. I have a1996 E-230.
Some say using a wrong type of atf is bad for the gears.

Thanks.