DaniloSilni

Hi All, just got a new to me GLS 550 that was dealer serviced only. I look forward to contributing a lot to these forums.

The search hasn’t yielded me any qualified results, and I am seeing conflicting information all over the Internet. Could someone please help me with specs and quantities of all the drivetrain fluids? Dealer parts dept was **** as well, and couldn’t get any tech’s on the phone.

Going to be doing the engine oil and tranny oil, but also looking for info on the diffs/transfer case and whatever else there may be.

thanks a bunch!


Here she is

chassis

Nice looking GLS!

Oft-discussed topic and well documented on this site.

Click the DIY link in my signature.

Go to the operating fluids site.

DaniloSilni

Thanks chassis!

wheatswake

Get the Benz-ninja setup. It will answer all your questions, save you thousands of monies and you will be able to customize systems/features.

chassis

Operatingfluids.Mercedes-Benz.com

chassis

I used GLS550 X166 with 9G-Tronic transmission, no off road engineering package, standard front and rear differentials.

https://operatingfluids.mercedes-benz.com/sheet/231.1

Rear axle with standard differential: spec 235.7, weight 75W-85, buy two 1 liter bottles
Front axle: spec 239.72, weight 75W-85, buy one 1 liter bottle
Transfer case: spec 236.12, no weight given, buy one 1 liter bottle
Transmission 9G-Tronic: spec 236.17, no weight given

Best practice is have the dealer or indy change the transmission oil. Front and rear axle, and transfer case oil changes are easy DIY jobs.

Buy new fill and drain plugs. Part numbers in the DIY.

The first step for drivetrain oil change is to confirm the fill plug can be removed. This avoids the situation where the oil is first drained, and the fill plug is stuck. The device is then devoid of oil and you would be in a pickle.

Buy all of the fluids at the dealer. Read the DIY for quantity.

FWP!

I put royal purple 75w-90 in the rear diff a long time ago, about 30k miles now. Engine oil I always buy this kit and do it myself - https://www.fcpeuro.com/products/mer...y-2761800009kt

DaniloSilni

Thanks to all for the help - wanted to give an update.

Just completed the transmission oil/filter/pan:

https://www.fcpeuro.com/products/mer...i-moly-22034kt

also did the engine oil, but using 0W-40 for some reason. For NY climate and driving, I do think I will switch to 5W-40:

https://www.fcpeuro.com/products/mer...761800009166kt

had a friend help me with resealing the cam valve covers where I noticed a lot of oil seepage - luckily It appears that there were no damage to the wiring harnesses:



While there, I changed all four cam magnets and also all four cam sensors from fcp and installed the wiring protection kit:

https://www.fcpeuro.com/products/mer...-2761560790kt1

Engine air filters were never changed after 95k miles even though the dealer said they were. The original 2016 manu date appears to prove otherwise:





New Bosch plugs, boots and coils were also replaced.

The front and rear diff/transfer case specs were driving me nuts, especially because three different MB dealers gave me three different part numbers so after much frustration and researched I just ordered the following and will replace in the next week or two when I get around to it:

transfer case-https://www.fcpeuro.com/products/mercedes-atf-fuchs-001989680313

both diffs:
https://www.fcpeuro.com/products/bmw...bi-83222295532

if anyone has front diff/rear diff/ transfer case drain and fill plug part numbers handy, I’ll take them!

Brakes and fluid was done by dealer recently. Down the line will be doing a coolant and power steering flush.

Thanks, all.