7g tronic DIY advice from people who have done it

[spike60]

I did this job on my 2007 E320 cdi 7g last year having previously done a 2000 CLK 320 5 speed. I bought a gearbox service kit from MB Newcastle who delivered promptly and answered questions quickly as well. From memory the kit was oil, filter, seal, sacrificial bolts and the plastic tube inside the box which sets the oil level for £154. Tools I used were torx sockets, small torque wrench for bolts (4Nm + 90deg from memory), 3L Wilko pressuring weed sprayer to fill the box and a Ebay adapter that screws into the bottom of the box to fill upover and a infrared thermometer. If using an infrared gun aim somewhere dull on sump, shiny surfaces tend to lower the reading. I already had the tools except the fill adapter.
There's plenty of how to guides on the net I can't really add to and as already said cleanliness is very important. I serviced mine at 154k, previously done at 118k a couple of years previously by MB and the oil was surprisingly black.Try not to make quite such a big mess I managed though!

 

[markjay]

Some more info here:

https://www.weistec.com/forms/weistec7229servicedata.pdf

 

[IFFY100]

Thanks for all the info thus far. I will be making my own trans fill tool. Where do I get the oil pan adapter to fill the trans? Merc don't sell the part, eBay sellers taking the pis to deliver. Any suggestions?

 

[steveq]

Hi,

I bought this one:-

Laser 4986 ATF Adaptor Fits Mercedes Benz 722 | eBay

12mm x 1.5 adaptor. Use with Laser Oil Dispenser Part Number. Included in Part No 5090.

www.ebay.co.uk

It says 'free delivery' ?

I got mine from Amazon but it is the same.

 

[IFFY100]

Silly me, I seen that last night and for some reason thought it was a week and a half delivery. Thanks for that mate.
Noting that you have also done the job on a 7g tronic, did you remove the look to seep fluid out of the drain plug when temp got to bang on 45 or around 43ish? This really is the only part I'm trying to properly understand, and whether I should drain the torque converter or flush a litre at a time as is demonstrated in a pretty good tutorial on line.

 

[W1ghty]

Silly me, I seen that last night and for some reason thought it was a week and a half delivery. Thanks for that mate.
Noting that you have also done the job on a 7g tronic, did you remove the look to seep fluid out of the drain plug when temp got to bang on 45 or around 43ish? This really is the only part I'm trying to properly understand, and whether I should drain the torque converter or flush a litre at a time as is demonstrated in a pretty good tutorial on line.

You want an isolating valve below the screw in sump adapter so you can quickly open it to see what’s coming out or not at 45 degrees . On my thread you can see the fluid transfer pump and isolating valve I have cheaply adapted to work

Mercedes E320cdi 722.9 DIY Gearbox oil change

Just finished the gearbox oil change . I'm embarrassed to say it probably took about 5 hours over yesterday afternoon and this morning . God know where the time went , probably lots of tool retrieval from the garage and a healthy dose of second guessing . I didn't intend to start yesterday ...

forums.mercedesclub.org.uk

 

[IFFY100]

Thanks w1ghty, that's the next thing

 

[steveq]

Noting that you have also done the job on a 7g tronic, did you remove the look to seep fluid out of the drain plug when temp got to bang on 45 or around 43ish? This really is the only part I'm trying to properly understand, and whether I should drain the torque converter or flush a litre at a time as is demonstrated in a pretty good tutorial on line.

I used an iCarsoft i980 to monitor the rise of the ATF fluid temp. I did have an infrared thermometer but decided that the one reported by the car would be more accurate.
I let the ATF get to that temp -- it comes up to the temp quite slowly so easy to monitor. When it was at the temp, I removed the adaptor and then just let the excess fluid spurt out until it largely stopped. Then I quickly put in the sump plug.

I drained the Torque Converter. There is a lot of ATF in the TC -- almost as much as is in the sump. It is slow to drain out too so you need to give it time (> 30 mins) -- maybe it flows back from the cooler? You'll need a friend to slowly turn the engine from the front crank pulley while you watch for the TC drain bolt to come around. Make sure that the engine is turned in the correct direction !

If you have stop/start there will be a little electric pump that you have to remove to get at the TC drain bolt. There are 3 bolts holding it on and an electrical connection. There are 2 little pipes about an inch long connecting to the gearbox that can easily fall into the the old ATF container and get lost.

That reminds me -- You'll need a big capacity and physically wide / long container for the old ATF. Some comes out the sump bolt hole when you remove it. More comes out the sides of the actual sump when you drop it. If you are careful you can loosen one corner more that the others so that it flows out that side. Yet more comes out when you take off the old filter -- that will run up your arm !! And then there is the ATF from the TC.

I would say you need 9 litres of new ATF as a minimum.

 

[wongl]

So the OP wants to service his car himself, but doesn't know the version of the gearbox, the tools, gaskets or fluid specs (despite being quoted in the owners handbook) required. MMMmm

I think this is fair enough and that is why OP came here for advice.

That said, my recommendation would be for OP to seek the parts from MB dealership in the first instance to ensure that he secures the correct parts (using his VIN number as identification). I have found that the ATF for my MB cars to be under £10 a litre from MB, so not much to be saved buying from other outlets with an increased risk of getting incorrect parts (or parts that 'meets the requirements' but not actually 'approved by' the manufactures.

I also found that sometimes saving a few quid buying non-MB ends up actually cost more than buying from MB. A case in point is buying brake pads from a well known European spare part supplier who were able to supply ATE brake pads around £10 cheaper than the MB brake pads. This works out to be circa 30% cheaper but the online listing failed to mention that the metal clips were not included and costed another £12. In the end it worked out to be more expensive than MB (which not only included the metal clips, but new caliper bolts and copper grease in the box).

 

[IFFY100]

To be honest I was rather annoyed at greenmanslks remark. I specifically in the titled asked for the opinion of people whom had done the job so to avert non appropriate replies. However though, I defo don't need to justify myself but can understand why people may think I'm clueless. Being a DIY'er, I approach a new task haven't done before with extreme caution and can therefore sound like a disaster waiting to happen. I have years of experience on different cars and have done many jobs from simple brakes to engine work. Because I am not a mechanic I want to ensure there are no ambiguities before going in. That said, all parts I have sourced have been from Merc. Sure some of it costs more but I know for sure the parts are correct. Next time I can order parts ebay etc since I will have all correct specs. Although seems merc in Edinburgh are a bit clueless as they swore to me that my car has SBC braking but seems to be not the case - thats after sending pics of the braking control module. And it appear they were defo wrong as I changed out the brake fluid last week and it was a success. Had the brakes been SBC then without STAR I believe the brakes cannot operate properly after fluid change.

Nowadays for some reason dealers are trying to undercut other dealerships so makes sense to buy from dealers as prices are usually not that different and parts tend to come with 2 years warranty too. An example is today: driver window regulator MB Edinburgh - £185, Newcastle MB - £170 delivered. Big difference if you ask me.

Now another question related to the DIY, has anyone attempted to flush trans as in this clip

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@ 12:10? It seems to have went very smooth for this guy but I read that switching car on and off during service of a trans is a no no? Or there is another method I saw on youtube that I cant find now which demonstrated flushing from TC (I think)

 

[W1ghty]

A guy called Scott Elliot on YouTube has done a good vid of a 722.9 transmission flush by removing the oil cooler line .

 

[IFFY100]

Actually thinking back now, the second lush procedure I spoke of was to disconnect fluid return line and pump fluid through the return line until fluid emerged clear (new colour). I think in that video the TC was also drained. Suppose the procedure above saves a lot of time as the TC doesn't need to be drained.

 

[W1ghty]

Don’t be put off by people saying you don’t know anything , everyone has to start somewhere . Until the last 5 years I had done very little .
I have now done all filters ,oil changes , glow plugs , spark plugs , brake discs , pads , caliper overhaul , front upper/lower control arms , supercharger oil , 7g gearbox service x2 , 5g service x2 , diff oil changes , various sensors , brake fluid changes .
I love tinkering and accept the odd mistake as part of the learning process , keep going buddy

 

[IFFY100]

Thanks for that. I just watched the video and a good explanation it was. I'm thinking though on this ocassion to use the flying mechanic method as it simplifies things slightly. With this method according to me you would drain pan, measure fluid, button pan back up, refill with old pan fluid measurement +1 litre extra, flush oil cooler line litre at a time and then replace exact amount of fluid used to flush.

wi1ghty - did you come across a situation where you had to add additional fluid after hitting 45 degrees? And i you did, did you jsut add more fluid while engine ran or switch off , cool down and go again?

Also is 45 degrees a sweet spot or anything above 45 is when temp should be checked?

 

[IFFY100]

Don’t be put off by people saying you don’t know anything , everyone has to start somewhere . Until the last 5 years I had done very little .
I have now done all filters ,oil changes , glow plugs , spark plugs , brake discs , pads , caliper overhaul , front upper/lower control arms , supercharger oil , 7g gearbox service x2 , 5g service x2 , diff oil changes , various sensors , brake fluid changes .
I love tinkering and accept the odd mistake as part of the learning process , keep going buddy

Cheers man for the encouragement. I too like you really only picked up pace in the last 6 years although I have been messing about with cars for about 12 years now. I too made horrendous mistakes but thats where I learned though. I just did a exhaust manifold on my nieces car last week and new arms on the BMW. Just wish I could get hold of a place where I can finance a ramp. You will I'm sure affirmate thats where things would really take off.

 

[jasonh]

Thanks for that. I just watched the video and a good explanation it was. I'm thinking though on this ocassion to use the flying mechanic method as it simplifies things slightly. With this method according to me you would drain pan, measure fluid, button pan back up, refill with old pan fluid measurement +1 litre extra, flush oil cooler line litre at a time and then replace exact amount of fluid used to flush.

wi1ghty - did you come across a situation where you had to add additional fluid after hitting 45 degrees? And i you did, did you jsut add more fluid while engine ran or switch off , cool down and go again?

Also is 45 degrees a sweet spot or anything above 45 is when temp should be checked?

There's a bit of tolerance on the oil temp. ZF gearboxes (which I'm much more familiar with) specify a temperature between 30C and 50C with 40C being ideal.

Basically the oil expands quite a lot with temperature so if you fill when cold then keep the fill plug open once the initial splurge has come out the oil will continue to trickle out as the temperature rises, the trickle won't stop. If you get the transmission too hot you'll effectively slightly under fill it.

I think the 45C is an arbitrary number but one that intentionally coincides with a cold fill and then a few minutes of idling whilst the oil circulates and you can run through the gears.

All of the guides sort of over complicate and mystify the whole process. You could do the same with an engine oil change and make a huge fuss over how to take the dipstick reading of oil level. You could put flushing oil through, etc.

Basically you take the sump off to change the filter. You overfill it a bit and then drain off the excess. It's not that hard but it is messy and gearbox oil is smelly!! If you do it regularly the fact not every drop of oil is changed doesn't really matter. I'm pretty sure that if you do it yourself the level will be set far, far more carefully than a garage would.

 

[IFFY100]

Thanks for the above. I have everything together now to start tomorrow. Just though need to check one thing - to drain the tc, the engine should be turned clockwise, have met mmmerc done anything differently where it turns counter clock wise?

 

[steveq]

90% sure it is clockwise however I suggest that you remove the engine covers on the top and the front and start the engine to see which way the crank puĺley is turning.
You will have to take off the covers anyway to get at the bolt.

 

[jasonh]

Have you done the deed? How did it go?

 

[IFFY100]

Did it. Will post about later when in the office