HOW TO: change the automatic gerbox oil and flush on a 722.6 'box

[momomo]

Well thats easy, undo filler plug, undo drain plug, drain oil, put drain plug back, fill with correct diff oil to the top of the filler hole and put the filler plug back! Easy huh?

 

[BenzedUP]

Well thats easy, undo filler plug, undo drain plug, drain oil, put drain plug back, fill with correct diff oil to the top of the filler hole and put the filler plug back! Easy huh?

Got no idea buddy, Olly is the expert here

but would be nice if somebody did a write for people like me

 

[grober]

Well thats easy, undo filler plug, undo drain plug, drain oil, put drain plug back, fill with correct diff oil to the top of the filler hole and put the filler plug back! Easy huh?

You are right-its a pretty simple job. However like all things the devil is in the detail.

1.You made no mention of the grade of diff/hypoid oil to use or how much.

2. Some limited slip differentials use different fluids and can have a lot of extra " plumbing" and a reservoir in the engine compartment. Wrong fluid could ruin the diff!

3.Getting the oil into the differential can be a bit of a problem if you can't get access from above and you have to "pump" it in via a large syringe. [ folks have used silicon/mastic guns and an empty cartridge in the past] or sometimes the oil comes in a "squeezy" type container with a clear flexible filler tube [ but I see less of these around now]



so a brief write up with pics would be good- will try to find one on line to link to.


p.s. I forgot to mention that you may require an socket set adapter to fit the threaded drain/fill plugs and maybe large breaker bar to free it off the first time you do this.

 

[momomo]

You are right-its a pretty simple job. However like all things the devil is in the detail.

1.You made no mention of the grade of diff/hypoid oil to use or how much.

2. Some limited slip differentials use different fluids and can have a lot of extra " plumbing" and a reservoir in the engine compartment. Wrong fluid could ruin the diff!

3.Getting the oil into the differential can be a bit of a problem if you can't get access from above and you have to "pump" it in via a large syringe. [ folks have used silicon/mastic guns and an empty cartridge in the past] or sometimes the oil comes in a "squeezy" type container with a clear flexible filler tube [ but I see less of these around now]



so a brief write up with pics would be good- will try to find one on line to link to.


p.s. I forgot to mention that you may require an socket set adapter to fit the threaded drain/fill plugs and maybe large breaker bar to free it off the first time you do this.

Sure Graeme, it was meant to be a quick reply to Josef to highlight its a fairly simple job. I did mention to fill to top of filler plug which in most cars is correct and also said use correct diff oil as well, so these kind of cover points 1 and 2, although not in detail as your post. I also do understand the difficulty of refilling sometimes because of access and methods used but as i was saying it was a quick post.

You are correct though, from a complete novices point of view its not that easy and a write could be helpful.

 

[grober]

Here's the spec for the W211. It would appear its a fill for life Synthetic.

 

[BenzedUP]

I just changed it today with Olly so many thanks to him and Jack, top guys!

 

[travelininstyle]

You've got my business - I like a through approach !

Every 40,000. I do it for £165

Mine will be due next major service,I am not convinced many would clean the sump pan to remove old atf fluid and flush out the last dregs either - that shows attention to detail and is absolutely necessary,or you are wasting your time,the new,clean atf,would deteriorate more quickly otherwise - it will be worth a trip down to Portsmouth - thanks for a fantastic posting.

 

[_Taz_]

Excellent write up

oddly enough I am to do the same to my old bus next week.

On a sidenote, I purchased a service dipstick & was going to do a pre-drain check, i.e. : get the temp up to normal, then insert the stick while in neutral & see the original level ( as I bet it's never been changed ) that way I have a reference to how much to fill, i case the dipstick is not entirely accurate )

from another forum the correct fill level is 60mm from the bottom of the stick @ 80deg C ?

cheers

Taz

 

[_Taz_]

:bannana:


quick thanks to C55 for the "how to".

I managed to do the change today under some humble ramps, however I was very surprised to see the condition of the ATF fluid, very black, no smell of burnt toast, no metal particles, a few bits of dirt fell in from the gasket when I took the sump off, no drama otherwise

Oddly enough I did really try to flush the gearbox out, but the most I could manage was 6.0l exactly, as C55 says, the actual hardest bit is waiting for the bloody engine to warm up to 80 - 90 deg c !

that must have been a good 20 min wait. The sump cleaned up a treat & now I've got 1.0l of spare fluid, may resell back to the dealer ( next time I decide to go there for parts ).

It's a shame the fluid don't say bright red long, even after a quick trip round the block, it's tinged brown already, must be the slug of oil left in the cooler.

nevertheless, the tranny is silky smooth now, much more responsive.

Doubt the main dealer would ever have done it as thoroughly ( in fact they only recommended 3.0 litres ! so they don't bother with the torque converter ! )

cheers

Taz

 

[BlackC55]

:bannana:


quick thanks to C55 for the "how to".

I managed to do the change today under some humble ramps, however I was very surprised to see the condition of the ATF fluid, very black, no smell of burnt toast, no metal particles, a few bits of dirt fell in from the gasket when I took the sump off, no drama otherwise

Oddly enough I did really try to flush the gearbox out, but the most I could manage was 6.0l exactly, as C55 says, the actual hardest bit is waiting for the bloody engine to warm up to 80 - 90 deg c !

that must have been a good 20 min wait. The sump cleaned up a treat & now I've got 1.0l of spare fluid, may resell back to the dealer ( next time I decide to go there for parts ).

It's a shame the fluid don't say bright red long, even after a quick trip round the block, it's tinged brown already, must be the slug of oil left in the cooler.

nevertheless, the tranny is silky smooth now, much more responsive.

Doubt the main dealer would ever have done it as thoroughly ( in fact they only recommended 3.0 litres ! so they don't bother with the torque converter ! )

cheers

Taz

Glad I could help.

BTW the temperature is gearbox temp not engine temp. It is very important it is correct too.

 

[_Taz_]

thanks, I had a thermocouple down the dipstick as a precaution, a "handy" how to pal, MANY thanks

Taz

 

[spock500]

Great write up, thanks

I am just doing my 1998, 300TD 722.6 auto box, have drained both the sump and torque converter using the small plug -

Is it necessary to undo the banjo and fit an additional pipe for a flush? or could I just locate the oil cooler and drain manually?


Cheers,

 

[BlackC55]

Great write up, thanks

I am just doing my 1998, 300TD 722.6 auto box, have drained both the sump and torque converter using the small plug -

Is it necessary to undo the banjo and fit an additional pipe for a flush? or could I just locate the oil cooler and drain manually?


Cheers,

You can do this.

Another way is to fill the gearbox with the 3.5-4L then run it for 30 mins then drain and fill again.

 

[spock500]

You can do this.

Another way is to fill the gearbox with the 3.5-4L then run it for 30 mins then drain and fill again.

Thanks, the ATF fluid is about £10 per litre so might opt for the cheaper option.

If I undo the banjo will it pump out the remainder of the oil cooler? I wasn't sure with it being an earlier box fitted with a TC drain.

Btw, where is the oil cooler?

 

[BlackC55]

It may have a drain.

 

[spock500]

Traced the oil pipes back to the cooler but couldn't see it as located up the top close the the rad.

I did find the two pipe unions which connect it though which are in good spot for draining.

Because the cooler is mounted high in relation to the TC most of it empties when you drain the TC through the small bolt, only about half a litre came out mostly from the pipes.

 

[spock500]

Remove the old filter and install the new one. Give it a thump to loacte it. They tend to hang down a bit. This is normal. Note the loacting clip.

Did mine today and it did hang down a bit which I thought was odd, the 'clip' you mention - is this the tang at the back which fits into a slot?

thanks

 

[BlackC55]

Did mine today and it did hang down a bit which I thought was odd, the 'clip' you mention - is this the tang at the back which fits into a slot?

thanks

Yes

 

[spock500]

Cheers for that,

Interestingly I left it overnight before final fitting and this morning noticed maybe another half a cupful of fluid in the bottom of the pan.

This was after a complete drain leaving for a couple of hours before refitting the pan temp (keep dust/moisture out during the night)

looks like there maybe some capillary action happening through the hydraulic passage ways, just a guess.

 

[merc711]

I am so pleased that I have found BlackC55's fantastically informative guide to changing the ATF and filter in a 722.6 box, as I'm just about to undertake this very job on my 2003 C200 CDI.

Unfortunately though, I lack the ability to fabricate something similar to Olly's cleverly adapted banjo bolt and hose set-up which he uses to drain the torque converter. Hence this question.........

Would the simple removal of the transmission banjo bolt altogether (and then running the engine for 4 mins as suggested) still allow the torque converter fluid to drain out successfully?

And if so, would the fluid come out in a reasonably controlled manner (ie would it be catchable in a bowl) or would it spray everywhere uncontrollably and under high pressure?

Also, it would be good to know before I attempt it, whether the fluid will come out of the transmission casing, the disconnected pipe, or both?

I am particularly nervous because I will be working in the cramped conditions and constraints afforded by a pair of lowly and ancient 9 inch high car ramps.

I'd also just like to take this opportunity thank everyone involved on the site for sharing such a superb wealth of invaluable information. It has helped me out so much on so many occassions over recent years.