ML 320 Transmission!

Dave from North Dakota: Help Please

I?ve got a 1998 Mercedes ML 320, a Starmark, with 100,227 miles on it. I bought the car in 2004, and have put the last 45,000 miles on it. It has been a delight on the road as well as around town. It has performed beautifully. Yesterday, it began to go into gear and change gear erratically at first, then going into gear only sporadically. I called the nearest ?authorized dealer/repair department?, 400 miles away, and they told me that they would have to examine the car to be more definitive, but that it sounded to them like it involved either a electronic sensor that confers sentience on the transmission instructing it to go into gear, or that there was something wrong with the internal workings of the transmission itself.

The driver?s manual, which I consulted before calling, stated that the transmission is a sealed unit and is not expected to need added fluid and or tinkering.

The procedure I followed: Ignition->(engine sounds normal with the expected idle RPM)

->move gear selector to the drive position->carefully ?step on the gas? (the engine would rev as expected when it was given fuel, but the car would either not move, or, occasionally, move very slowly).

My Question:

1) Your opinion

2) How much of what I?ve been told is just pure sunshine?

3) If it needs a new transmission, a ball park guestimation of the cost, anywhere in the outfield will help.



Check your fluid level first, engine running, hot, vehicle in park on a level surface. How is the level/condition???


The owner’s manual states that the transmission if sealed at the factory, and cannot be opened except by a duly trained and equipped repair center.

Not true. The dealership will have a part number for a “Fluid Checking Only” dipstick. The only purpose of this dipstick is to check the fluid, and it does not stay in place while driving.

There is a “sealed” locking cap on the end of the filler tube. If your transmission has never been serviced, or had the locking seal opened, there will be a black locking pin holding the cap on. If the original seal has been opened there will be a distinct brown colored pin.

You’ll need both the dipstick and the new locking cap/ pin. Around $60 for both.

Being able to check the fluid also means you could do your own transmission service. The torque converter has a drain plug, as does the tranny pan. just walk the converter around with a large pry bar on the fly wheel until the plug presents itself. The rest is easy, as long as you keep things very clean along the way and use the proper torque setting when reinstalling the pan.

I think a service will make a big difference. There are a lot of MB sealed transmissions running around with 100k to 200k + miles that have never been serviced. Not good. Change the fluid and filter every 60k miles for a very long life.

Price on the factory rebuild tranny is around $2200 on the pallet. It comes with a warranty good at any MB dealership if the do the R&R.


Whats the price on the trans fluid? BMW’s was way high

You can get it for about $14/qt through worldpac:

That’s not a bad price for the Febi branded fluid.

It is my independent belief that the transmissions weren’t sealed for life. I think they were sealed to stop an owner from putting in the wrong type of fluid.There’s just so many brands and quality levels out there.

The transmission fluid level should be checked by the service technician at every service, but that doesn’t seem to be the case. I see plenty of virgin sealed caps on 100K+ mile vehicles.
Again, service these transmissions every 60,000 miles for maximum life.

Logically, there is a bit to think about with MB fluids these days.
These high end fluids are designed for extremely long or non-existent
service intervals. This makes then unique. But, who is to say that any
modern Mercon transmission oil, if changed with frequency, would not
work as well.

The chemistry of these ATF’s is difficult to fathom without having a
lubrication engineer/chemist around. We lost ours years ago and
haven’t had real input since.



Thanks. Your information has been helpful as well as enlightening.