I read mine from the cluster. I think Acta_Non_Verba posted there was a 15F to 20F difference compared to the scanner?

Will keep a look out here if you post any questions. Have fun with the diy!

 

Update - the $150 iCarsoft MB-III / 3.0 unit from Amazon….. worked! I can easily call up the trans temp and the interface is a lot better than the outgoing model. If you’re gonna own a MB product, this is probably the smartest $150 you’ll spend.

https://a.co/d/bPPlsvJ

 

Ok - Transaxle service completed. All in all, it’s very straightforward but still left questions as far as how this is being *really* done at AMG / MB dealerships. Like others have mentioned, I’m not entirely sure the WIS is 100% correct. I’ll explain below, as well as add some of my own observations.

Again, big thanks to Stenzel, Acta and Katie and all the others who contributed in here. It’s good to see others who aren’t afraid to service what they own!

Baseline info: My car is a 2018 AMG GTR with just under 4,000 miles on it. One owner prior. To the best of my knowledge none of the transaxle services had been completed before. Car had yearly oil changes and that’s about it. Wasn’t driven much.


Put together your materials and tools:



The “screws” aren’t just regular Phillips-head screws. This is actually an aircraft mechanic style bit with slightly offset grooves. You’ll see what I mean. I used a #6. Katie knows what I’m talking about with her background, (I don’t know the proper name for the bit)



First, remove all underbody panels, reference post above by LASunset for stacking and removal info. During reassembly, I somehow used an extra two aluminum bolts, so “something” is tighter than it was before. No clue how or where I did this, because every part of underpaneling with a threaded hole got a bolt put back into it. Perhaps from AMG they missed two?? Either way, I had spares to replace them with.

Panels removed will look like this:





Here you can see the brace/cylinder that needs to be removed

It conveniently blocks the aft “differential” drain plug. (There is also a forward differential drain plug)


Now, following the WIS, I began work on the “differential” side of things.

Draining procedure:


You don’t have to, according to WIS, but I collected and measured the amount removed. Most of the fluid came from the aft differential drain plug. Literally maybe an ounce came from the forward one. (Car has sat for around two months prior to service, so maybe this is why?)

The stream will just barely miss the also convenient scaffolding directly in your way. Nice.

4,000 mile diff fluid (left), brand new Shell Spirax (right). Given how easy this is to accomplish, I’d say do this every 5-10k miles depending on your driving. First change is dirty probably because it’s “break in” fluid, ie, when things were newly mated together.

All in all, I was able to only drain about 2.3L from the diff. Seems a little bit on the low side, compared to the 2.8L others were seeing. Again, I’m assuming AMG themselves were the only ones who touched this car sooo….?


Next we use the Motive unit to fill the differential:



This little $60 guy gets a TON of use. Had it close to 10 years!

More scaffolding in the way lol



Fill until fluid runs out. Then after spillage stops, cap off with filler plug. Then, idle car for 60 seconds to allow diff fluid to enter the cooling loop. Lastly, top off Differential until it spills out, wait until spillage ceases, and reinstall filler plug.

Differential took on about 3.0L of fluid. Shocking difference, in my opinion, from the 2.3L that was drained off….

There was no where for the fluid to go. No leaks. Didn’t “consume” it. So, did AMG themselves not follow this procedure properly during initial fill???

Now onto the DCT portion:

Drain DCT from drain port (only one, and next to the forward Differential drain port that I got next to no fluid out of).



I removed 5.2L of fluid in total. That’s after letting it drain for a long long while. About 0.5 less than most are removing on here…. Again, underfilled from the factory?! Also, metal scaffolding in the way of fluid stream. Makes a nice mess and gets everywhere initially, not too difficult to control the stream afterwords. Just a bit annoying.

4,000 mile DCT fluid. Yeesh.



I added an extra liter above the 5.2 removed, so a total of 6.3 (included 100mL extra for “usable loss”, ie, fluid that can’t be transferred from bottle, in tube, etc



Didn’t need a fancy filler tool adapter. My hose fit nice and snug in the opening and went in about 3/4” so zero fluid made it’s way past the opening. Nice.



With 6.3L installed, it was time for the final stages. “Warm transmission up to 60C while shifting through all gears”

Ok, cool.

After 45 minutes, I went from 20C in my heated garage, to 30C, where temps stabilized. Uhhhh…. Ok. This is clearly not gonna happen here.

So, I went for a very very gingerly drive, keeping the revs at or near idle as recommended by WIS. After another 45-60 minutes of very slow start stop forward reverse uphill downhill driving, I was able to get temps to read out at…… 45C. Oooook. Meanwhile, on the dash, transmission temps were reading at the top of the scale of 89C. Huge split. Knowing the dash numbers are wonky at best (this is how insanely off they are) I had my suspicions trusting them. It even made me second guess the readout from my OBD scanner!

inout the car back up on the lift and using my IR gun, confirmed the low 45C-ish fluid and DCT temperatures. This was after a total of 90 minutes of running and driving. The trans cooling is so good, you will likely never see 60C under these conditions (again, following WIS here…). Opening the fill screw also confirmed these cooler temps, as no fluid spilled out (again, I was at 6.3L here).

Strange the dash temps showed such high values, but as confirmed, the fluid was only warm to the touch. Cooler than hot tea. Oh well.. plan B:

I next employed the “Katie-Scientific method”. I removed approximately 1.3L (1L was captured, the rest got basically everywhere including my pants that are now in the trash). I then reinstalled another 800mL bringing my current level to approximately 5.8L, or about half a liter more than I started with at 5.2L. I feel like that’s closer to the more correct amount, after suspecting underfilling from the factory.

If I ever see 60C gearbox temps in the summer months coming, I’ll check level again and see if anything drains off. I highly doubt it will, and honestly, I’d say a good number to use for future reference is 5.8-6.0L. If you have the luxury of checking level easily like I am fortunate enough to, that’s not a bad way of keeping tabs on things.

Anyways, hope this helps. I don’t see this as the “brain surgery critical” procedure that the WIS seems to make it out to be. Some of their steps are not even possible to follow, so just use common sense and you’ll be fine.

Good luck and happy wrenching!

 

I had the same experience when removing/replacing the diffuser/under-panels on my GTR Pro (for a different reason). Puzzling.

Amazingly detailed report ... exactly what I'd expect/want from someone who works on my aircraft (not that I have one). Thanks.

 

Katie is the aero engineer, she’s the bright one lol. I just move the “high speed aluminum” around from time to time

 

Ha! Didn't realise that. Updated my post. Your pics look amazing.

My used diff fluid color is darker than yours but DCT is certainly cleaner. Very strange and I am at about 7k miles.

Motul 300 75w90 and Motul DCTF (for next time) as well.

 

Found this on Ebay. Looks like it would fit and certainly cheaper than the MB too at $40+

 

Looking to do this service with locally sourced parts. I called the dealer and asked them if they had rear differential fluid for my car. They asked for the last 6 of the VIN. They proceeded to tell me that they in fact had it in stock and that the PN was 001 989 52 0310. Looked it up and this is Castrol Syntrax Transmax 75w140 - not even the same weight as the factory recommendation. Could this dealer be THAT WRONG on the rear diff fluid for my 2018 GTR? What The Freak? side note: Only option I have found for sourcing a reasonable amount of Shell Spirax S5 ATE 75W-90 - 5 Litres is from the UK company Lubefinder. It will cost me $165USD to get it here but unless there is a reliable alternative, I see no other stateside option at the moment.

 

Yeah, they very well could be that wrong.. haha. Lubefinder is where I sourced mine for the Differential side, I went with really good DCT oil from Motul for the gearbox side which can be had locally in the USA. I think all in, you're still under $500 for what at the dealer would have been a pricy, not to mention possibly wrong-fluid-install. I really didn't trust the average MB tech on this one. Really need to either DIY it or go to a VERY reputable exotic car shop. There's nothing that is "rocket science" about this (and I hate that term because rocket propulsion is one of the most simple and ancient methods out there - I digress), so don't feel like its anything you can't accomplish on your own. I just wouldn't adhere too closely to the temperature fill dynamic method with a GTR or BS because the cooling loop won't ever let you get there. Keep somewhere between 5.5-6.0L in there (DCT side), and you'll be good to go.

 

$370 in consumables in the US for this service. Will get it cracking and post a video when I am done.
FCP Euro I get the fluids and plugs for the life of the car - bonus.

 

Cross post: Does anyone have the part number for the o ring / gasket on the differential fill plug? Apparently the gasket is the only part requiring change on this fill plug - on all others you are supposed to change the plug and gasket. Strange.

 

Hi,

Here too, the entire screw with o-ring should be replaced.
There is also no part number for this o-ring.

Best regards

Stenzel

 

Alternative: Motul 300 75w90 which is what I used.

 

I saw that above on posts but is it not concerning that not even the Motul website has this as a recommended lubricant for the 2018 AMG GTR? Just sayin.....

 

Did the transaxle job on my wife's SLS GT acc to WIS last week.Unfortunately I don't feel comfortable now because:
I drained more Spirax than I could get filled in afterwards. If I remember correctly it was 3,5 l out and 2,8 l in.
So what could be the reason?
- Getrag/MB overfilled it (I assume strongly that I did the first change)
- car/transaxle was not levelled out and stood with front higher than back
- maybe I missed a bulletin that states that later gearboxes from SLS GT have to have a higher fluid level and in order to get more in you have to fill it with back lifted

I know everything just said sounds odd.

best
Fred

Besides I agree with the problem of getting temperature of the hydraulic part to 60°. And yes, you let the engine run at ilde for 1 minute and check again the Spirax level. But in the meantime the oilcooler is depleting again. Do you have to be in a hurry?

 

Feels like this reason. Was it on a lift or floor jacks?

Acta's experiment was 3.9deg higher in the back. Though I do wonder if it's biased to the front, it might drained more as well.

 

I start to understand. Had to read Acta's post multiple times. And yes, the point is that my garage has a slope too.

First I tried the Spirax job with my electro-hydraulically operated "mini"-platform-lift. It has only a max raising height of 1.5m, but due to the ceiling I'm limited to .8m operating height. Far away from being able to stand comfortably upright but still a very good help. Since it sits on the garage floor it is also affected by the slope. When I got doubts after the first fill because of the difference of fluid In/Out I now lowered the car's wheels not only on the concrete but on top of pieces of a wooden countertop so that the chassis sits now high enough to get access to the gearbox with rear fill plug. Since I used inadvertently two different thick materials the front wheels are now 4cm higher than ground BUT rear only 3,2cm which brings an additional slope factor too.

So, what I will do next is to do the bubble level job. Unfortunately you cannot take the bubble with the gearbox as a reference since there are too many reinforcement struts below the gearbox. See Acta's AMG GT.

 

Instead of:
- fill up the transmission with room temperature oil
- plug the fill port
- drive the car off the lift/jacks
- drive the car aggressively (get ticket) to raise the temp to 140F
- get the car back on lift/jacks
- remove fill plug
- add oil
How about we heat the oil to 160F slowly in the oven? The oil expands ~4% for 100F so we loosen the caps to allow for the expansion. The extra 20F is to account for some cooling of the oil when it comes in contact with room temperature transmission.
Crazy idea?

 

Or just measure what you removed and replace with the same amount.

 

Green Hell,
This is a creative solution. However, I suggest the oil would cool very very quickly by the metal it comes in contact with.

 

My car I just acquired 2018 GTR had almost exactly 3L diff fluid drained. This is definitely the first service for this car... nothing had been touched.

 

I want to thank everyone who contributed to this thread for helping me perform a transaxle fluid service. I had trouble finding the original factory fluids and used the following successfully:
- Fuchs Titan FFL-4 Dual Clutch Transmission Fluid (602007209), from FCP Euro, 6+ Quarts
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube (SVGQT-EA), 4 Quarts

The only thing that I guess I did not focus on during all the reading was the need to run the engine for 1 minute after filling the gear oil and then topping it off again. This did require more fluid after the initial fill. I was also surprised that I only drained about 5 quarts of the transmission fluid. I've driven the car for about 100 miles and everything seems smooth as silk. I did buy some Shell S5 ATE gear oil from Europe off Ebay as a backup, but everything is going well ...will keep it for a few months and then sell it if not needed.

Also, I was able to get the transmission fluid up to 140 F while still on the lift. You could not rev the engine very much because the traction control kicked in. But I kept shifting from neutral to reverse to drive and pressing the gas. Took about 20 minutes but got up to temp no problem. I left the transmission oil fill plug open during this process and oil steadily leaked out while it warmed up. Then, when the temp got to 140, I turned the engine off and quickly topped off the trans oil one last time. Seemed to do the trick, everything is running silky smooth.

Thanks again everyone!

PS. I'm a lifetime Toyota guy and hope this is one of the more reliable Mercedes haha!

 

PM me when you are ready to sell. I'm interested.

 

I recognize that it doesn't need to be replaced, but still interested to find out how it seals (o-ring, copper washer?). I don't even see the plug or seal on EPC unless its part 100, which I doubt.

 

Between the 1) scan tool and 2) the dash readout, I note that WIS specifically says to "read out hydraulic fluid temperature using diagnostic system." I'm just wondering if the Autel you use reports the same figures as would be reported in Xentry. Before I do mine, I hook up my Launch first (I don't have an Autel) and then Xentry and see if they agree.

UPDATE: Launch & Xentry Agreed on the transmission temps.

Call me skeptical if you must, but when my Launch reported DTCs and my Xentry didn't I was confused until I found that MB simply reprogramed Xentry to hide these 2 implausible fault codes. See https://www.tsbsearch.com/Mercedes-B...54-19-P-061447