mguerrero

So, finished my radiator swap today and figured I'd just do the tranny service while I was at it - replaced the filter and gasket - attempted to replace the transmission plug that sits on the side (its a big round plug) the new one was NOT sitting in well so i decided to just re-install the old one ... lowered car let it run for a few mins and then poured 3 liters of MB ATF - went to try to put the car in park to take for a short test drive so I could check the fluid levels and ....... nothing ... the car will NOT go into gear! tried it a few times, turned the car off several times and still nothing .... I did hear some sort of noise coming from underneath near the tranny ...

any clue what it could be??? Like I said all I did was disconnect that plug, replace and gasket and filter and thats IT!

GatorMB

I recently put a conductor plate and interface plug in a buddies ML430, while it did not fix his problem it gave me some insight for servicing my own when it gets ripe.

Fluid level is important here, measure what comes out. analyze the transmission for leaks while working on it, and consider the loss of fluid when adding.

Interface connectors are not all the same but the o-ring seals are, never believe what you are buying on e-bay will be a good fit especially AMG chassis.

When unplugging the trans cabling, battery is best dis-connected. If fluid leaked into the connector and saturated the pins it might cause a no shift.

Noise can be from lack of fluid or another system acting up under a coincidence. If the fluid level is proper, try resetting the trans memory.

engine off turn key on and all doors closed, all accessories off, nothing on but the ignition in run and hold the gas pedal only to the floor for 3 min. (silence) you will hear a click and all is restored.

If fluid saturated the interface connector it might have cooked the TCU (trans control unit).
double check for fluid in the connector and bent pins as well.
The symptoms are not common problems but since you have tampered with it, might be an easy fix.

good luck, Gator

MarcusF

You said you did this, in this order:

1) Swapped radiator
2) Replaced transmission filter and gasket
3) Replaced the $5 o-ring, but decided to reinstall the old one.
4) Lowered the car.
5) Started the car
6) Let the car run for three minutes
7) Then added three liters of transmission fluid.

A couple of things. First, did you drain all the fluid and then start the car, as in "dry"? If so, that's a very bad idea.

Second, many people use a transmission dip stick. The dip stick has a cold level and a hot level. After draining the fluid, swapping the filter, buttoning up the car, and ensuring it is level, then they add fluid until it reaches the cold level on the dip stick. How do you "know" you needed 3 liters? How do you "know" that's not too little or too much. Too little or too much can damage a trans. The reason for the hot level on the dip stick is after the trans fluid is warmed up then the fluid is topped of to the hot level. Hot is not a relative term. A STAR box or an infrared pyrometer are the most common tools for determining whether the fluid is hot and there is a spec for it.

If you don't have a dip stick, you may want to get one before moving forward.

mguerrero

Hey MarcusF!

Thanks for chiming in ... so, what ended up happening is I poured in the Tranny oil in what I thought was the tranny tube , thats what I thought it was ... what it really was was the engine oil dipstick tube even tho my car does NOT have an engine dip stick ... so AFTER i poured it in is when I started the car and yes the tranny pan was dry of any fluid other than the OTHER 9 qts if oil left in the torque converter as I didn't drain that ... this is the time I attempted to move the car and it wouldn't move so I never ran it on the road dry ... don't know if thats what you meant ...

also, today I drained the engine oil and flushed another 3 qts of engine oil thru it to get any tranny fluid out and also poured 1 qt of tranny fluid into the correct tube and put it in gear and it moved a couple inches which is all I was planning on moving it I just wanted to see it move at all ... the car is still parked until tomorrow until I can get more MB ATF fluid ...

also, I got the amount to pour in from a tech at my local MB dealer which he quoted 3.5 liters - and today when I poured the old oil into empty liter bottles it was about 3.2 liters so if I take into account what I lost when I removed the ATF fluid lines from the radiator I'd say its pretty close to the 3.5 ... so I will start with 3 and then ck level ... do I need to drive after I pour the remaining qts to get accurate level or should idling just do it? also, where would be the place to ck the fluid level? just point the infrared thermometer to the pan??

it can't ruin anything to run the engine with tranny low on fluid, correct?

your input is appreciated

MarcusF

Typically, 3 liters or so of fluid are added. The car is started and put in reverse for 30 seconds or so, and then drive for 30 seconds or so, and then back in park. With the car running, check the dipstick. If it's in the cold region go back and put it in reverse again for 30 seconds or so, and drive for 30 seconds or so, and then check the level again. At that point, if the fluid is in the cold region on the dip stick, then the car is taken for a drive. When you come back from the drive, point the pyrometer at the transmission pan and hopefully see 80C. Assuming its 80C, insert the dipstick and see if the fluid is in the 80C region on the dipstick.



As for ruining transmissions, I've never burned up a Benz trans. I have run an old GM Turbo350 very low on fluid and nothing went wrong. I ran an old Ford C4 low and it burned up the clutches. Hopefully you're fine. If not, Sun Valley charges about $2500 if I remember correctly. Installation is extra.

GatorMB

It would be hit and miss,
If you raced the engine the trans might have suffered a bit but a quick shutdown after hearing the noise should be good.

Gator