ok to flush a transmission this way?

[greythunder]

I own a jeep Cherokee in edition to my 92 300d 2.5. I flushed the transmission this way and had great success and I was curious if I could do the same on the benz.

the theory is that draining the pan only gets a few quarts, and even draining the torque converter you still don't get it all.

I could take it somewhere, and have a machine put way too much pressure in the system to flush and cause all kinds of problems.

the procedure is as follows:

1. drain pan from plug.

2. drop pan and change filter

3. fill pan to correct level with new fluid

4. disconnect trans cooler line going to radiator and clamp inside 5 gallon empty bucket.

5. take funnel and stick in trans dipstick tube.

6. have assistant start the car and at the same time commence to dumping fluid down funnel while the transmission's own pump is flushing old stuff into bucket. at the same time your assistant is going through the gears with a second or 2 stop on each detent.

7. keep fluid pouring into funnel (have at least 4 gallons ready) until fluid going into bucket turns clear and cherry red.

8. turn car off, and top off you suck out fluid to get to appropriate level.

[Zulfiqar]

Yes this is entirely do able, but is it worth spending extra 2 gallons of ATF just to remove 1 or 2 qts of trapped ATF.

however - there is no problem in doing this. The other factor that is a "gotcha" moment with your MB is the ATF level on the dipstick. In dead cold condition the cold level on the dipstick is not the 30C mark, its 11mm below it which is exactly where the dipstick curls up and becomes a pointed arrow.

Filling it to 30C mark on a dead cold transmission will cause problems as its overfilled.

[97 SL320]

The method will work but at a high cost of fluid. At most I'd go 2 or 3 QT.

When towing a trailer with my truck I'd pump out 2 QT every so often and refill without pulling the pan.

I'd rather change fluid more often.

[sleepstar]

to be honest i'm not sure if you can get the atf down the fill tube fast enough to keep it filled. the fluid really POURS out of the cooler lines.

[greythunder]

but is it worth spending extra 2 gallons of ATF just to remove 1 or 2 qts of trapped ATF.

this is true, my jeep did not have a torque converter drain, so you could only get about 3 quarts of 9-10 total. how does one go about draining the torque converter?

and yes it comes out in a hurry in my jeep as well.

[compu_85]

Since the MB automatic has a drain plug on the torque converter a "normal" drain gets most of the fluid. Some does stay trapped up in the trans / valve body though.

-J

[Ceristimo]

If you really want to flush the transmission I think a better way of doing this is not to run the engine continuously.
I did a tranny flush on my wife's previous car, and after dropping the pan, changing filter and filling it back up decided to flush it.

I disconnected the transmission cooling line running to the radiator, put it in a bucket with volume markings and had my wife start the car. I'd yell at her to shut it off after collecting 2 quarts (which really only took like 10 seconds at the most). I would dump 2 quarts of fresh fluid back in (which really took A LOT longer then 10 seconds..) and rinse and repeat until what came out of the line was nice and red.

This way you're not running the transmission too low. Just a thought. I think it took me a good 5 gallons of tranny fluid just to flush everything out, and it kinda felt like a waste to be honest. Flushing out perfectly good fluid like that. There has to be a better way, but I wouldn't know what.

[engatwork]

As stated above, better to run it till you get a quart out, shut down and add another quart, continue doing this until you have used at least 8 qts in the unit.

This is if you can't drain the torque converter.

[w123fanman]

The way we're doing it in my bro's 300SD is an initial change then a couple changes after that. You can get bulk ATF from Sams for pretty cheap, 12 quarts for $23.48. It's some off brand but I figure it's fine if it says it meets Ford/GM standards and on those old transmissions Mercedes just specifies ATF.

[vstech]

You could also lift one tire, put car in gear, and rotate a tire to have the rear pump slowly pump fresh fluid out the cooler, and then hook everything back up, and fill to the low mark on the stick... assuming you drained the torque converter.

[greythunder]

what type of trans fluid does our cars use?

[mytmousemalibu]

Originally Posted by vstech

You could also lift one tire, put car in gear, and rotate a tire to have the rear pump slowly pump fresh fluid out the cooler, and then hook everything back up, and fill to the low mark on the stick... assuming you drained the torque converter.

That won't work, the transmission's pump is driven off the torque converters snout and thus the engine has to be turning over to pump fluid.

The line method does work and well. You will inevitably waste some fluid though it thats bothersome.

[vstech]

Originally Posted by mytmousemalibu

That won't work, the transmission's pump is driven off the torque converters snout and thus the engine has to be turning over to pump fluid.

The line method does work and well. You will inevitably waste some fluid though it thats bothersome.

Most MB auto transmissions have a rear pump as well...

[mytmousemalibu]

Originally Posted by vstech

Most MB auto transmissions have a rear pump as well...

Really? Thats odd, never seen or heard of such a thing before, not saying your wrong, just surprised

[charmalu]

Sure a lot of worry over a small bit of old ATF left hanging in the Tran after a drain.


Warm up the transmission, warm oil drains best.
Drain the pan, drain the Convertor, remove the pan, wash it out, (I use gas to wash it out)
then use spray carb cleaner to flush it clean and air dry.
Do not use a rag or paper towel to wipe it clean, you get lint into the trans.
Replace the Filter.
Do not wipe of the ATF dripping off the bottom of the trans. Remember....lint.
Replace pan with new gasket.
Be sure to replace both drain plugs, and with a new copper washer.
Add proper amount of ATF. think my 85 held like 6 qts, add 5, warm up the trans, then add
the 6ts qt a little at a time till you get it up to the fill line...hot.

I think I had something like 360K on my auto before I swapped in the 4-spd manual.



Charlie