2017 GLS550 135k Service

[rpaoness]

This is mixed in with the purchase thread, so figured I'd start a new one just for 1st major maintenance:

To do:
Engine air filter (already purchased)
Cabin air filter (already purchased)
Engine oil/filter (already purchased)
Transmission oil/filter (need to buy)
Spark plugs (need to buy)
Passenger window switch (gift)
Rotate Tires
Install Trailer Hitch (already purchased)
Install Hitch Wiring (already purchased)
Decide on harness extensions/ cam sensor replacements needed to prevent oil entry (parts ahead or inspect-and-order?)
Fuel filter (Benz maint sheet says 150k mi) (need to buy)

[kevm14]

Two comments.

1) For the cam sensor and adjuster harnesses (8 total), there is a Mercedes P/N for one of them (so four) and the other will require the aftermarket (such as eBay). I can try to dig that all up to show you the options. But I did want to mention that if all you did this round is inspect and clean, that is ok.

OEM cam position sensor extension harness (x4):
FCP: https://www.fcpeuro.com/products/merced ... 2711500156
Dealer: https://www.mercedesbenzpartsshop.com/o ... 2711500156

No-name aftermarket source for all 8: https://www.ebay.com/itm/374594648746?f ... R_bs1tfdYw

Slightly better name but not sure if just adjuster harnesses or all 8?: https://www.ebay.com/itm/115706746208?f ... R_bs1tfdYw

I ordered mine from ZZP (before I realized I could have gotten OEM cam position sensor harness extensions). I had a bad cam harness out of the box but they sent me a new one and I was good. It set a code though the car drove fine.

2) It is possible the SUVs are different than the cars, but in the cars, the "fuel filter" is integrated into the fuel pump assemblies. So replacing the fuel filter could mean replacing hundreds of dollars of pump(s). This should be investigated. If, on the other hand, it is just an inline filter of some kind, great. None of my cars have such a thing though.

OEM low pressure fuel pump, actually not that bad: https://www.mercedesbenzpartsshop.com/o ... dhcw%3D%3D

[kevm14]

I would add tire rotation. Full rotation if the wheels and tires are the same size would be fronts cross to rear and the rears straight forward. Else, just swap right and left side assuming they aren't directional.

[rpaoness]

Looks like transmission fluid is 236.17 per a link posted in the GL/GLS test drive thread. Valvoline claims compliance. https://sharena21.springcm.com/Public/D ... 162d889bd3

Since it looks like Valvoline MaxLife universal meets GM Dexron VI, Honda Z1, Allison TES295, Benz 236.17, and Chrysler 68218925AA (weird that they appear to have come out with 68218925AB, but Valvoline hasn't listed it on their data sheet?), I think I'll just wind up stocking and using a ton of MaxLife. I think the only think I have that I "shouldn't" use it in is the 2002 Jeep Grand Cherokee w/ 42RE that calls for ATF+4, but that's going to be fore sale in a couple days.

I wonder if I can get MaxLife 5 gallon pails cheaper.

[kevm14]

Claiming compliance is not the same as OE certified/approved. It is common for many fluids manufactures to "recommend" an application. That is what Valvoline is doing. I am not comfortable with that because inside of their own lists, individual OEMs don't even recommend the same fluid for the applications that Maxlife is claiming it's suitable for. In Mercedes land for example, 236.14 and 236.15 are different viscosities AND colors (red vs blue). Mercedes specifically forbids cross-application of those. The stakes are too high for an experiment.

I would select a real 236.17 fluid (which in Mercedes land I believe is NOT backwards compatible with .14 or .15) or pay the money for the Mercedes fluid. Or at the very least find some anecdotes on people using non-OEM approved fluids and having a good experience.

Even this: https://www.rockauto.com/en/moreinfo.ph ... j07EYxDz2x

Look at the back of the bottle on picture 2. Specs: none. Approvals: none. Recommendation: 236.17.

This may be a helpful reference: https://mbworld.org/forums/glc-class-x2 ... hange.html

[kevm14]

This may be a helpful reference: https://mbworld.org/forums/glc-class-x2 ... hange.html

These people seem unphased by the "recommended for 236.17" though I also don't think anyone realized the difference. The important point is, people are running these non-approved fluids and no one has reported any disaster. That said, I still am highly suspicious of an all-purpose transmission fluid. I would either spring for the OEM fluid (which I agree is outrageous but the frequency is far less than an oil change) or at least run a specific fluid recommended for 236.17 (which exist, Rockauto lists a few).

I'll philosophize for a bit because it's fun. Transmission fluid has a few jobs:
- Carry heat away (any hydraulic fluid will do this)
- Viscosity characteristics (important to maintain flow and pressure per design expectation)
- Friction characteristics (critical for the torque converter clutch as well as all of the shift clutches)
- Detergency (small passages that clog will ruin a transmission pretty quickly)
- Temp/oxidation resistance (this impacts how it handles high temps and generally how long the fluid can be expected to perform at spec)

I feel like #2 and #3 can't really be done by a one size fits all fluid, at least not in a way that makes me comfortable.

On the other hand, since it's not my vehicle, go ahead and use Maxlife and I want to know how it shifts and holds up over the next 50k. That's useful data.

[rpaoness]

At least on the Ram/Jeep 8 and 9 Speed ZF transmission it seems there are many 300k-500k examples of Maxlife users, so its at least good in those applications. Not sure on the Benz front. My suspicion is that clean/good universal oil is far better than used-up OEM stuff to a point, especially if at least Valvoline says they're confident that it's recommended for 236.17 applications. I'm also more likely to change at 40k - 60k mileage if it's less expensive to change, vs. running more expensive oil and being more inclined to try to run it longer...

[kevm14]

At least on the Ram/Jeep 8 and 9 Speed ZF transmission it seems there are many 300k-500k examples of Maxlife users, so its at least good in those applications. Not sure on the Benz front. My suspicion is that clean/good universal oil is far better than used-up OEM stuff to a point, especially if at least Valvoline says they're confident that it's recommended for 236.17 applications. I'm also more likely to change at 40k - 60k mileage if it's less expensive to change, vs. running more expensive oil and being more inclined to try to run it longer...

Given how sophisticated transmissions have become I guess I'm surprised that Maxlife is claiming to be so widely compatible. I suppose they have a high incentive to invest R&D to make a fluid that's actually compatible and can be marketed as advantageous to both independent shops and DIY people. Would be nice if they just went the extra mile to get the real approval. I know that costs money so there is an argument that if the fluid is the same, you'd rather spend less on it. But my argument is, I actually don't think the Maxlife is approvable for MANY of the OEM specs they claim to meet or exceed. The question is, why? And does the deviation cause any real impact to you? My argument is, it's pretty hard to get through all of this conclusively so I'd rather just spend the couple hundred dollars on fluid I know is approved for the application.

Maybe I can find some discussion at BITOG about whether people are trusting Maxlife for their recommended application.

Yes, new fluid is better than used up OEM fluid but that's a false dichotomy. That's like saying that Walmart Supertech is better than not changing your oil. Yes, it is, but those are not your only choices.

On the other hand, if you actually service more frequently because it's cheaper and easier, that is likely a benefit in the long run.

Oh, that thread talked about draining the torque converter so you need to look into that. When I drained the torque converter on my S550, the kit from FCP Euro included a new plug with the sealant on it. That was nice but perhaps not mandatory. That plug spins at engine RPM (at like a 5" radius, or more) and it would be a disaster if it leaked. Another thing to think about at least.

[rpaoness]

Ordered trans pan/ 4x wiring harnesses from MB Warwick - shipping was $70, so hopefully either you can snag these or I'll drive out there sometime. Order 4802 placed 4/25/24

Based on ECS Tuning's "kit', I also ordered the oil pipe and guide tube they included. Order 4803 placed 4/25/24.

Ordered plugs from RockAuto - Bosch ZRSII3320

[rpaoness]

I forgot about the passenger rear airbag that may be original. I could just run it until it has some sort of symptom. And/or I could do a soap spray test to see if it's weeping yet.

RockAuto: $195 for Bilstein

Benz: $433 exchange, $448 new

ECS claims the OEM are Bilstein:
https://www.ecstuning.com/Mercedes_Benz ... ir_spring/