Treft4

I just purchased my 2000 ml320 with 126,000 miles and plan on changing all the fluids, chassis lube ect... I have been looking into how to flush the tranny and my understanding is there is no drain plug in the t/c. I would like to perform a full flush as I want to have all services up to date, my question is, is there any way to drain the t/c on a 2000 model year 722.6 tranny. If not does a multiple pan drain provide any real benefits over a single drain. Thanks for any feedback I'm sure ill have more questions as I proceed with services

m1943

I had a mechanic do it for me. The mileage is like 145,000 or so. It wasn't a flush, just a simple drain with the pan being removed. Only about half of the fluid really gets replaced. Less than 5 quarts, I believe. It was a couple of months ago, so I may not remember correctly. There is no dip stick; so what we did was measure how much fluid got drained and pour in the exact same ammount of fresh fluid. I used Pentosin ATF1. Upon removing the old filter I noticed it was a Febi, so this wasn't the first time that the tranny was being serviced. I plan to do an another drain and fill in the near future.
Some people do like a BG flush, that costs more, and is more radical. I'm sure there are cons and pros to that. Drain and fill is less intrusive, you just have to use the proper fluid. I wonder if it's possible to get a dip stick for the tranny, did they even make those?

Treft4

Yea they sell the dipsticks on eBay $20-$60... Depending on the brand... I had heard some where that if you disconnect the return line from the cooler (after u drop the pan and refill) stick the end into a container ( clearly marked at 1 liter) and run the engine... Drain 1 liter... Fill 1 liter... Drain 1 liter... Fill 1 liter etc until it runs clean that would effectively drain both the t/c and the cooler... Just trying to find out if anyone has done this? Is it safe? Would hate to leave so much dirty fluid in there... If anyone has any other suggestions?

m1943

Most people just say drain, fill, drive a few hundred miles drain and fill again and so on. Other people do like a BG flush, all the fluid gets replaced. I've never heard of any other options other than these two. Transmission fluid is meant to last a pretty long time, (for ever, if you trust your dealer) so if you drain and fill every once in a while, it will always be pretty clean. That's just my opinion, I'm not a pro.

Jerry Easley

Yes Treft4, I have done the full-flush described above by disconnecting the return line from the cooler. It is safe. It works just fine, and is economical, and it is simple 'just methodical. I did this solo on jack-stands.

3 notes.

1. Secure the 'loose end' of the return hose either with a helper or a clamp so it doesn't 'flop around' when fluid flows.

2. First replace the amount of fluid drained at the start of the procedure, or 5 liters. Set-up the 'pump and drain' items. EDITED: See attached AR27.55-P-0100A Flush out automatic transmission and torque converter

3. About the dipstick. Insert it into the tube until it stops - there will be excess length. See included photo.
The dipstick is universal to different lengths of guide tubes w/different vehicle configurations. The distal end has a small triangular protrusion near each end - that is stopped by the design of the guide tube near the valve body.
To understand it for yourself - while the pan and filter are removed insert the dipstick until it stops. Then you can see how 'deep' into the pan it protrudes, and the 'how far in' question will be answered in living color.

4. On attached 'Check Oil Level' the note between #9 & #10 indicates no need to check fluid level hot unless: "Only perform steps 10 to 14 if shifting problems occur."

gkrumian

Agreed. It's a great way to flush any 722.6 transmission.