ML AUTO BOX FLUID CHANGE

[panason1c]

kaleem,
The box was working perfectly well before i changed the oil/filter, i carried out the work purely because i dont believe that any oil is good for 'lifetime' ..after the oil change the 'box felt even smoother on the gearchanges.

Here is an interesting article from an American MB website............



Filled for life?
The 722.6 Automatic Transmission uses a special oil and is said to be filled for life. The oil can only be purchased through the Mercedes-Benz dealer using part number 001-989-21-03-10. A 722.6 holds about 9.3 liters and the fluid is sold by the liter. Checking the fluid is accomplished by breaking off the red locking seal located at the dip stick. the lock is replaced after the oil is checked. Use part number 140-991-00-55 for a new lock. There is no dip stick to check the ATF. You need a special tool to check the fluid on all 722.6 transmissions, part number 140-589-15-21-00. The oil level is a critical factor in transmission shifting. See Service Information 27A95105 for details. When you refill, or check thetransmission fluid level make sure that you check the level with the special tool and at the correct temperature. The latest information from Germany is that we should fill the oil to the MAX line. Not overfilled, just maxed out. This is said to improve shift quality. At normal level it is possible for the oil to form air bubbles. The increased level helps to minimize this. You might want to remember to try this on customer complaints involving shift quality before you replace any component. Along with setting the adaptation you would be surprised to see how much of an improvement you will see.

The Automatic Transmission fluid is said to be filled for life. We never specified who's life. (Yes, they actually wrote that in this!-DG) The transmission control module contains a program that keeps a running count of the "calculated" cndition of the ATF oil. (Note from Gilly-I believe this was deleted from the modules right around 2001-2002, not there anymore-DG) The factors that affect the oil are time and temperature. The counter is incremented with engine running time and incremented greater with higher ATF temperatures. The Hand-Held Tester (now SDS-DG) displays a numerical value that represents the value of the calculation. At some given point in time Germany will tell us (still waiting, evidently-DG) which number means its time to change the oil. For now there is no service interval for the ATF oil. If you replace a transmission you should re-set the counter back to zero to account for the new oil. If you are doing internal work and you are replacing the oil you should also re-set the counter. It is acceptable to drain the oil out into a clean container and reuse it, provided it was collected using the MB filter funnel. Remember to flush the converter and kines before installing the new transmission. You should also replace the converter if the transmission was HEAVILY contaminated with metal. Make sure you return the converter with the transmission to warranty. Fine metal particles in the bottom of the pan are allowed. (I think what they mean here is that fine metal particles are considered an "acceptable" condition, do NOT replace transmission, as you will see if you read on:-DG)

The Color of Money:

We have been conditioned to judge the quality of the transmission fluid based solely on it's color and smell. We have no way of judging the frictional quality. The rules have changed. (didn't Iaccoca say that too?-DG) The bright red color that we are all used to seeing may not be what you see when you look at the ATF in a 722.6. The reasons that the oil looks differently are as follows:

1) The oil may appear dark red due to the graphite material that the friction discs contain. This does not change the characteristics of the oil. Do not change the oil or transmission if the oil appears dark red or even if it has a yellowish tint to it. The color will change with time and temperature. As of 10/97, the manufacturer of the oil has agreed to put more red particles in the oil.

2) If a copper color is seen in the oil pan the bushings of the front or rear planetary gear set may be in the process of wearing out. Inspect the bushings and if they are defective replace the complete transmission. If they are not defective, then the transmission is repairable.

3) If a silver color is present in the oil it may be a clutch and steels moving up and down on the hub as they are being applied. This is normal! Use your best judgement here. If the particles are fine they should not cause problems as they will be trapped in the filter. The fluid could be drained, including the torque converter, and the lines flushed and the valve body should be disassembled and cleaned, replace the filter of course. This usually takes care of the problem. If you take the time to inspect and clean each slide valve for ease of movement and base position you will have a better valve body than a new one from spare parts. In more severe cases where the particles are large, then something is in the process of self destruction and the transmission should be either replaced or repaired. Don't forget to check the electrical solenoid valves. Shine a light through the top of it and see if it "leaks". If you drop the transmission oil pan (I think they mean "remove the pan"-DG) and you find yourself feeling like a miner panning for silver, or knee deep in a graphite colored mud, then it's time for a new transmission. You may have noticed that the new pans are painted black on the inside. The metal particles show up better against a black background as opposed to the previous unpainted silver pan. You must get used to seeing some metal in the bottom of the the pan, with this transmission this is normal.

4) Smell the oil. You know by now what burnt oil smells like. If it looks burnt, and it smells burnt, then its burnt.

Example: Try looking at the adaptation values for K3. If the numbers are high, then you have a K3 problem. If the customer is complaining about shift quality going in and out of third gear, repair K3.

5) Make sure you understand the complaint before you disassemble the transmission. Use the HHT (SDS now-DG) adaptation screen values along with the shift application chart to see which shift members are applied during your customer complaint so you will know where to concentrate your efforts when you disassemble. Remember to disassemble the transmission like a surgeon, you need to observe the condition of seals, rings, c-clips and shims as well as being aware of the potential for missing parts.

Repair or Replace:

Use the transmission oil pan as an indicator when deciding to repair or replace the 722.6 transmission.

The following pictures (sorry folks, I'm transcribing the written part only, no pictures-DG) are for reference as to which transmissions should be replaced and which should be repaired.

(picture shows a black pan with some small "dots" here and there-DG) This is a normal oil pan for a 722.6. The fine particles are normal. Do not replace this transmission.

(can't tell what's "wrong" with this picture-DG) The brass colored particles may be a sign of a bushing problem. This transmission may be repaired.

(can't tell by the next picture either what the problem is supposed to be, rotten copies!-DG) The metallic sludge indicates that there is a major mechanical problem. This transmission would probably cost more to repair than to replace.

(This picture you can see obvious copious amounts of metal shavings, a pretty good coating of it-DG) This picture also indicates internal damage has been done. This transmission would be replaced (as well as the TC and flushing lines and cooler, etc-DG).

 

[kaleem]

Hey panason1c
Thats great. Thanks for that article. Had a nice read through and im tilting more and more towards having mine changed. Ive consulted Geroge Fraser already and hes been honest enough to tell me that he wants me to be around to inspect the state of the oil when its drained from my transmission. Which is a good thing, especially now after reading this article.
Ill be exactly sure of what to expect. Will fill u in as soon as i get the job done. (Mid - feb approx) Thanks again!

 

[psmart]

Just completed the auto box oil change, the old oil was very black and the filter was very sludged up with lots of 'gunge in the sump...........also, using the 'workshop' MB dipstick prior to draining showed the oil level to be very low by about one litre, on the relevent temperature related dipstick mark....(the box was at full operating temp')...
The only problem is that there was no torque converter drain plug, (there is one on earlier models apparently), so i will drain and refill the box again in about 10,000 miles to 'dilute' any old residual fluid down.
Glad i did it for peace of mind......if anyone has any doubts about changing this 'for life' fluid then you should see the fluid and gunge that was drained from mine..there is no doubt that this fluid DOES need changing (i would suggest 60k intervals) in the interests of preventative maintenance.

Panason1c, I know this is an old thread, but reading your posts on this and the other site, thought you may be able to advise.

Whilst I have my car stripped down, Im contemplating draining and refilling the autobox oil. Any problems or pointers you feel need mention? Also, any ideas on why auto-fluid would appear to be coming from the 'sealed' dipstick top and a small amount of fluid on the underpan of the autobox?

 

[panason1c]

Hi psmart,
Definately change the filter and fluid!.......... My 'box was noticably smoother afterwards, the problem with cars produced after late '99 is that the torque converter drain plug was discontinued which means that there are about 3.5 ltrs of fluid left in the TC that cant be drained.....my plan was to 'dilute' it down by doing another change about 10k miles later but i actually continued on to do another 30k miles by which time i noticed a slight 'flare' developing on the 3rd to 4th gearchange!.....I was lucky enough to come across a transmission from a nearly new (less than 1k miles) , written off ML which i have now fitted to mine.

The fluid on the underside of the pan is most likely from the transmission electric plug connector and a new 'modified' plug complete with seals is available, it is very quick and easy to fit (20 minutes) and proved to be the source of a recent leak on my trans ...the part number of the plug is...A203 540 01 53 ..It is described as a 'spacer' and costs £3.65.
I doubt it is the rubber sump gasket as they provide a very reliable seal.
Another area to check is the base of the dipstick tube where it enters the tranny....just renew the 'o' ring if it looks damp.

The sealed dipstick cap (which is a solid seal ie..not vented) is also fitted with an 'o' ring so perhaps it needs replacing?, though i wonder if maybe the transmission could be overfilled as i dont think fluid should be reaching the height of the diptube ....i forgot to replace the cap on mine on one occasion after checking the oil level and it was left off for a couple of days but the area was totally dry with no evidence of fluid being splashed out when i eventually noticed it missing.
Hope this helps.

 

[panason1c]

as i dont think fluid should be reaching the height of the diptube ....

Just to clarify that i mean 'splash' from the gearbox...not the actual fluid level

 

[psmart]

That's great, thanks a lot Panason1c, appreciated.

... will order up the parts whilst here in Germany (seal, O'rings, filter and oil) and replace them next time I'm back home. Everything looks in good order on my car, very little rust etc (albeit I keep it clean underneath and regularly oil/copper spray it). Was just a little suprised at the oil, as Ive not experienced any gearbox problems, other than 2 years ago when it refused to move out of Park or locked into 1st when left at -30'c (or colder, given the wind chill) for 1-2 weeks! The indie topped it up then and has been fine ever since, so perhaps they overfilled it. Other than that, my high speed antics (>100mph for 600miles++) could have pushed up the fluid.

I assume you didnt get photos etc when you changed your autobox/transfer case? A howto would have been very useful. I've changed boxes many years ago (my Skoda manual, Rover SD1 Auto), but things always look difficult if you have to think it out yourself. Hopefully Ill never need to change the box/transfer case! I'm in the process of writing a Howto for the exhaust/turbo/manifold, there are many people on this board who would consider it a piece of cake job, but no doubt there are many who may find it useful.

2 quick questions, do you need to get the gearbox oil warm before draining and do you have the part number for the gearbox dipstick?

Thanks a lot, and will post the problem on this thread with a photo.

 

[panason1c]

The removal/install is very easy and straightforward....i did the whole job on my own at a steady pace in 6 hours (just needed help to lift the tranny on the install)

Try this...detailed removal + pics..

Edited link............http://www.pointedthree.com/disc/forums/showthread.php?tid=1523&posts=6&start=1

The gearbox will drain much more efficiently if the oil is warm/hot.

The dipstick PN is.....W140589152100.....(Measuring stick)

Trans filter......A140 277 00 95

Pan gasket......A140 271 00 80

Trans oil......A001 989 21 03 10 (7.5 ltrs....but you will only need 4 ltrs if the TC is not drained)

Lock pin (This is the 'seal' on the diptube cap)....A140 991 00 55

 

[psmart]

All parts ordered up, so just hoping for a good sunny weekend.

I must say though, that I found working on the ML a pleasure, compared to previous cars, everything well ordered (albeit you have to do a fair bit of dissasembly, for example wheel arch trim to get to exhaust/turbo bolts) and logical. Will post an update as to state of oil, reason for leak etc. Car has 59.5K on the clock, so hopefully, no suprises.

Many thanks.

 

[panason1c]

Just thought to mention.........If you unplug the aforementioned electric plug on the side of the gearbox (after sliding a locking tab downwards) and oil dribbles out then that will confirm that it is indeed leaking as it should be totally dry inside the connector.

Dont worry about any 'resets' or upsetting anything by disconnecting/reconnecting the plug...........nothing happens.

 

[psmart]

Just a quickie...

... got all the bits today, that spacer looks damn big!! With regards to the dip stick, it has two sets of pointer (4 divisions with arrows between) saying 20` and 80`.... which level do you fill upto, sounds daft, but normally these dipsticks are graduated or have min/max, not degrees!

 

[Stevie A]

Just a thought. I had to buy a fluid extractor to remove engine oil due to a stuck sump plug. The same type of thing can be used to extract transmission fluid. As far as levels are concerned - you can measure what has come out and refill with the same amount of new fluid. It would be an easy way to change the oil. Although it wouldn't get rid of gunk on filter but it would still be better than running old oil. The machine sucks oil out the dipstick tube by hand or elecrtic pump action. Sealey made the one I have. Mityvac make them too.

 

[panason1c]

... got all the bits today, that spacer looks damn big!! With regards to the dip stick, it has two sets of pointer (4 divisions with arrows between) saying 20` and 80`.... which level do you fill upto, sounds daft, but normally these dipsticks are graduated or have min/max, not degrees!

The 25 and 80 sections are refering to transmission temperature..cold (25 degrees) or hot (80 degrees)....The best method of using the dipstick is to get the engine and gearbox up to normal temp (80 degrees) by doing a 20'ish mile run and then checking the level....which should be halfway between the 'max' and 'min' marks on the upper 80 degree scale of the dipstick.

 

[panason1c]

The 25 and 80 sections are refering to transmission temperature..cold (25 degrees) or hot (80 degrees)....The best method of using the dipstick is to get the engine and gearbox up to normal temp (80 degrees) by doing a 20'ish mile run and then checking the level....which should be halfway between the 'max' and 'min' marks on the upper 80 degree scale of the dipstick.

...........car on level ground, engine idling and selector in 'P'

Dont be concerned that there is about a foot of dipstick still sticking out after you have fully inserted it into the dip-tube.....and dont (as i did!) forget to replace the cap when you have finished.

 

[psmart]

Thanks a lot for that very useful info, Panason1c, wouldnt have guessed it easily. Didnt even occur to me that the two levels were temperature related, and as for the foot of measuring stick sticking out of the dipstick, that would have got me seriously concerned, it would all have probably gone into the box, but what would have been damaged in the process, gulp!

I'll take pics of the leak, and if it is the spacer, will let others see how to identify the problem and use your very useful advise.

Steve A's suggestion of sucking the oil out, I wonder if that would remove the fluid in the Torque converter, ie. Drain all the oil out of the drain plug, remove the filter and magnet, put the plug and pan back on and then try sucking out the remaining fluid. Only concern is wether any debris will be sucked up into the workings should this method be used.

 

[panason1c]

I have a 'sealey' fluid extractor and they are very useful, especially if you overfill the tranny and need to drain a little out.....however, the tranny pan really does need to be dropped to renew the filter which is relatively small and over time could easily become restricted through gunge build-up.....also, while the pan is off you can examine any 'debris' on the bottom of it and assess the general condition of the tranny.

An extracter will not help regarding draining the torque converter, the only way to properly drain it is to remove it! (the TC drain plug was discontinued circa 1999)

With the pan removed leave everything to drain for an hour or so.

Might be an idea to dilute what was left in the TC with another oil change in, say....15k'ish miles?........Using the fluid extractor would then be a good tool of choice as the tranny filter obviously wouldnt need renewing.

 

[panason1c]

Off-topic.....Here's one for you to reply to psmart .....

http://www.benzworld.org/forums/w163-m-class/1270678-any-ml270-chip-mod.html

 

[psmart]

What a weekend, car completely finished, in time to drive the fiat at 100mph all the way back to Germany!!!!

Your advise was spot on panason1c, thank-you very very much. I will post some pics tonight, but the leak was the Spacer for the electrical connector. It took less than 1 hour to drop the pan (couldnt get the drain plug to release, so I didnt want to force it, just copper spray greased it for next time), replace filter, put in a magnet (My model didnt have the magnet, so Merc recommended I add it), change seals/spacer, put back together and refill. Took about 5 hours to put the whole exhaust manifold, turbo etc back together. The car absolutely flies now, no noise, Im tempted when Im next back home to re-flash the performance ECU map... time to show the new ML a hot set of heels, as it will be pumping out almost the same bhp/torque

Once I've got the remapped ECU back into the car, will post my figures on the link above. Just drop down to Rufforth or Sutton Bank and test it on the runway

 

[panason1c]

Cheers psmart,

I couldnt undo my drain plug either..lol...not a lot of point in forcing it if you're dropping the pan anyway..

 

[psmart]

Colour of oil

Quick question on oil colour, after scanning the forum and not getting really the info I need (the search mechanism really needs updating on the forum, as no doubt this topic has been covered before).

The colour of the fluid leaving my box was a dark golden brown, very thin with a little bit of bronze shrapnel, not too much, and would have thought this normal as the friction discs wear. Was your fluid this colour at 60K, or have I been pushing my box to hard, ie. high speeds for long durations? The smell of the fluid was the same as the new fluid going in.

 

[Myros]

Try and compare it with the new stuff going in

two old jam jars and a bit of forethought means you can compare one against the other. Its hard to tell from the dipstick and wiping cloth.