I have just completed an Automatic Transmission Service on my 2013 E Class W212 (estate) 7G-Tronic Plus using the ATF 134FE Blue Oil and thought I'd share my experience. As a guide to my skill-set, I am an engineer with experience in the motor vehicle and aircraft industries, although I’ve mainly been in management role for last 15 years so a little rusty on the tools! Before deciding to do it myself, I made enquires with well over a dozen workshops (all in UK); however, I got many different accounts of how job is completed, how much ATF is drained and even what ATF is used. Also, my experience at my local Mercedes main dealers was so poor on a technical level I thought there is no way I would let them near it (never seen such rushed technicians). I seriously advise you to research this job thoroughly before you attempt it as it is not a simple or quick task, although I’m sure I could do it in a couple of hours next time. I do not intend to go through the whole process as I based my preparation on the following links which were a massive help. http://www.benzworld.org/forums/w212-e-class/1721568-photo-diy-722-905-7g-tronic.html https://www.youtube.com/watch?v=_-72EN_pqUU&index=10&list=LL7zLee2QMFgmwBI3enyWc3Q&t=708s[/url] You need access to a decent and varied tool kit, including torx bits, hex bits, ¼ & 3/8 socket set, torque wrench and torque screwdriver (to go down to 4Nm), an angle gauge and a sump adapter with pressure pump to refill. A ramp really helps also; doing this at ground level would be difficult and risks contaminating the transmission with dust etc when the sump is off. Don’t be tempted to skimp on original parts. Buy new screw plugs and washers for Torque Convertor (TC) and Sump (couple of quid each) and you MUST get new sump bolts as they do stretch when fitted (the new ones are noticeably shorter than the ones you remove). Obviously you also need the green overflow pipe, sump gasket and filter too (I also got new magnets for £2 each). As for oil quantities, some ‘service kits’ only supply 6 litres of ATF oil (even Mercedes parts department said it was 6 litres); this is insufficient for the full system. If you drain the system properly (including TC), you will drain approximately 9 litres, so 10 litres of genuine ATF 134FE is the best and most cost efficient option (5 litres was cheaper than 3 individual litres anyway). You definitely need a filling adapter and a way of pressure filling the sump. I had an adapter machined from brass and also constructed a pump assembly using a new garden sprayer and 15mm isolation valve. However, in the end I managed to get hold of a Sealy 3 litre ATF filler system which I used instead (this was the right decision). IMPORTANT REFILL INFORMATION – READ BEFORE STARTING If you want to accurately measure temperature of ATF when filling, you need a Digital Management Reader plugged into electronic management system. I took various temperature readings before draining; results were as follows: • Thermal infrared thermometer of sump (near drain plug) read 48 deg C, • Multimeter with temp sensor attached to same point read 52 deg C • MODIS (STAR type system) plugged into vehicle readout was 68 Deg C • Actual oil temp when drained after about 15 minutes from other readings was 66 deg C. Clearly, there is a significant difference between the actual temperature of the ATF oil and what various instruments read from outside of the sump. Of course you could always try to measure the amount that was drained and fill with the same quantity. More on refilling below. LESSONS LEARNT –TOP TIPS Draining Torque Convertor (TC) Buy a new TC screw plug before you start – this has a copper washer and threadlock and costs about £3. You will need to access the bottom pulley to rotate the TC to expose the plug. This is done by removing the final part of the air inlet pipe and then removing the cover that sits in front of the main pulleys (both are push fit - no screws and accessed from inside the engine bay). Once the crank pulley is exposed you will see 4 torx bolts holding it on NOT a 27mm bolt. I used a torx socket (E16 I think) and half inch drive ratchet on one of the 4 bolts to rotate the engine clockwise; this can be done from underneath once the pulley cover and bottom covers are removed. I had a buddy tell me when TC plug was central with the access hole. Note – a slight rotation of crank pulley rotates the TC significantly more, so gently does it! Removing the TC plug was a bit tricky as getting a socket mounted hex bit to fit was tight. I used a ¼” drive hex bit for cracking and torqueing the plug, and a long reach, ball ended hex key for final removal and starting thread as it gave much more freedom of movement. You could use a 3/8 socket hex bit but would probably need to disconnect an exhaust clamp and intercooler pipe. I decided this introduced un-necessary work and risk of leaks, so managed with 1/4inch and hex key setup – be careful to make sure you fully insert the hex key or you risk rounding the plug head! TOP-TIP –make sure you use a magnetic bit holder as if the TC plug falls off when removing or inserting it, then it will be extremely difficult to retrieve it out of the housing! There is a tiny drain at the bottom of TC housing so don’t bother trying to catch ATF through the access hole, access is really limited and I ended up with oil running down my arm. One TC started to drain I rotated the engine so the TC plug was at the 6 o’clock position (fully down) to drain all oil – this took at least 30 minutes. I then rotated it back to the access port and fitted the new plug with washer and torqued to 10Nm for M8 – again be careful not to drop plug inside TC housing! Finally, I sprayed cleaning fluid into housing and let it drain out to clean it as far as possible. Draining Transmission To remove the main transmission sump you need to remove the exhaust mounts at the rear of the sump – it is only 4 bolts and makes life so much easier (the clamp traps the rear of the sump). Around the front of the sump there is a cable clipped in 3 places. Use a small screwdriver to help release these clips. You also need to remove a torx bolt that secures the cable to the front corner of the sump on the driver’s side (UK right hand drive) before you can access the main sump bolt. Make sure this cable is well tucked up out of the way or it can catch on the sump during removal. Top-tip – after draining sump and ‘knocking off’ overflow pipe to drain additional oil, refit old sump plug to prevent spillage when removing sump. Be prepared for a surprisingly dirty sump and magnets! Drain the sump as described in links – the tip about tilting sump to drain more oil by loosening one side first is worthwhile. You need facilities to clean everything thoroughly. Reassembly and Refilling Follow links for refitting (I smeared a little new ATF around the filter rubber o-ring to assist fitting but NOT on the rubber sump gasket! Click the overflow pipe in place. Make sure the sump gasket is fitted properly and the little lugs are located on sump rim. Don’t forget the magnets! I used a torque screwdriver to tighten the 6 new aluminium stretch bolts as only require 4Nm and many wrenches don’t go this low. Then I used an angle to gauge to add a final 180 degree turn (this could maybe be done with a t-bar – however, I heard the bolts can easily snap if overdone). As for filling, I followed Mercedes WIS which said add new ATF in one go (not in stages); they advise to measure the quantity of drained oil and add a litre. Run up to 45 deg C using the MODIS/STAR system plug into car. It did not take long to reach 45 deg on the electronic readout system. Based on my earlier tests ATF temperature tests, it would take much longer to read ‘45 degrees’ from outside the sump. By the time you register 45 degrees outside the sump, the ACTUAL ATF temperature is likely to be significantly higher; this will result in excessive ATF draining out so be careful (this was from Mercedes information). Be prepared to be quick with sump plug! Finally, there are a couple of rubber drain hoses on the e-class either side of the transmission housing which let out a lot of water during the warm up period. All in all this isn’t a particularly awkward or fiddly job, but it does require time, the right spares and proper tools. Considering the cost of a new transmission if it goes wrong make sure you consider the pros and cons carefully. After the new ATF circulated and ‘cleaned out’ old residue, I definitely noticed improvements in smoothness and even responsiveness of gear shifts (in truth I’ve never been overly impressed with the Mercedes autobox). Considering the state of the oil and the debris in the sump and on magnets, it definitely needed doing. In hindsight, I would recommend the ATF is changed at 50-60k miles instead of the 77500miles recommended. Overall, an extremely satisfying job (so long as transmission doesn’t leak or pack in as a result). Hope this helps and good luck!