The dip stick will frequently give a false reading after draining the torque converter and transmission.
It can easily take several hours to re-establish the correct level.

The safe - correct procedure:

* Drain the fluid.
* Measure how much was removed.
* Write down how much was removed.
* When you are prepared to begin filling the transmission...
* Put four quarts in, with the engine off.
* With the engine running; Add the remainder of what came out.

You want exactly the same volume of fluid back in the transmission.
** Too little will burn out the clutch plates.
** Too much will cause foaming, and possible spewing from the dipstick tube.
Danger: Transmission fluid can flash fire - burn on a superheated exhaust manifold or catalytic converter.
Examples:
Fire Caused By Transmission Fluid out Dipstick Tube - Ford F150 Forum
"HOT OIL" MESSAGE, fluid boiling out of dip stick tube causing fire!!!
At the beginning of an investigation of a vehicle fire, the following scene presents itself
Transmission blowing fluid out dipstick tube - Ford Explorer Ranger Enthusiasts "Serious Explorations"®

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1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

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I am unable to remove the red cap on my transmission dip stick. It appears to be a press and twist type release (ala Groelsch beer), but I am unable to remove it this way?

Any advice?

After reading all the negatives associated with changing infrequently changed transmission fluid, I think I should at least keep it topped up...

1982 300SD

I assume you know that the cap is retained by a lock tang that has to be disengaged.

The advice for measuring what you drain is excellent, particularly with cooling systems. You know for sure if the system is full, or still airbound.

you flip the black part out that's right under the red cap, then you pull out the dipstick

often topping up is a problem itself
you have to properly recalculate
min and max positions are for the operating temp of the oil -> 80 C.
(30 min of driving will give you that temp.)

folks do cold check and if below min mark they add atf
which is not a good move.

ATF top-up?




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__________________
w126 500SEC gen II euro, powered by OM617 turbo stolen from 84 300SD 2.88 diff,EGR blinded
next wish/project: w114 coupe OM603 powered

For those of us that pics work easier.

#1 and 2 are of the dip stick as it is in the tube ready to run.

#3 is how the black keeper looks when its ready to be pulled. It just snaps back out of the way while being moved as if you were raising it to the hood.

Attached Thumbnails

     

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Roy, isn't this method a bit imprecise in that you don't know how much fluid is in the filter? Why isn't it better simply to drain pan and TC, let everything drip for a good long while, and then add the amount specified in the FSM? Plus there's the practical matter of not catching every drop in a container....I always lose a bit of fluid here and there.

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14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

And you have to be sure there was the correct amount of fluid in the transmission before draining.

Sixto
87 300D^2

You are unlikely to damage the transmission by putting the exact same volume back in..
You must still check the fluid level MANY times, adding as needed to correct for MINOR fluid losses..

The ounce of fluid trapped in the filter will be compensated for during top off.

I am getting several calls per day:
New owners performing this service, and putting to little back in + taking it for a drive that burns out the clutch discs..


.

I wonder what accounts for people putting too little back in. I would think, if anything, the tendency would be to overfill.

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Are there dangers to overfilling other than having fluid spew out the dipstick tube?

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

An interesting observation....I wonder if that's what I'm experiencing. Just did the ATF on my 91 300D. Drained pan and TC and let things drain for several hours...and replaced filter. Added EXACTLY 6 liters. Drove it around the block. This morning (car running, cold ATF) the level is at the min mark, whereas it should be 12mm below min mark. Guess I'll just drive it for a while and see if it drops a bit.

__________________
14 E250 Bluetec "Sinclair", Palladium Silver on Black, 153k miles
06 E320 CDI "Rutherford", Black on Tan, 171k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver, 142k mi, wastegate conversion

19 Honda CR-V EX 61k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife

Hey WHunter this is an opportune thread !

My experienced MBZ mechanic (indie post-dealer mech) just did several maintenance items on my 79 300D including trans fluid and filter.
He did place the removed fluid in a measuring jug.

I think he was a bit fatigued today because he got confused with the amount out and replaced.

I convinced him to double check and it needed more.(trans not engaging)
Eventually it 'seems' like he added about 2.5 mm (about 1 inch )
over the dip stick's max line when measured HOT (on level ground, engine running in park) after the 30+ minute drive home.

He did tell me it was a little "over filled" but that the older transmissions would not be hurt by it.
Whereas the newer trannies are very sensitive to overfilling (i.e. damage).

updated: drew out 21 ounces (0.65 qts.) Now its about flush with the top MAX line of dip stick.

I will keep an eye on it but can anybody give a definitive answer to whether the 1979 W123 auto trans can suffer mechanically from this amount of overfill ?

I have no problem removing some excess fluid later......
nevertheless I prefer to know.

Thanks whunter !! good thread !

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

My story on transmission fluid is that I have a friend who took his mercedes diesel to walmart to have the transmission serviced. They drained the fluid and then decided that the transmission did not have a way to refill it so they handed it back to him without saying anything. Apparently they could not get dip stick/filler off.

After a couple of blocks the transmission quit transmitting.

He eventually got them to get him a new unit.

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

Sweet scam !!

what's the address?

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD