If you are about to undertake your 20,000, 40,000 mile, 60k service etc on your GL 350 diesel, I wanted to point you to the post below on the M-class X164 Forum.

The DIY Guide over there works perfectly for the GL 350 too - everything is exactly the same. I searched around in the GL forum and didn't find anything as good over here.

https://mbworld.org/forums/m-class-w...e-warning.html

Druker, I have the same vehicle as yourself and tow (Airstream Safari 30). When I did my 40k maint in addition to the transmission service I also changed the transfer case and front and rear differentials. The rear diff was dark but clean of any metal sheen, front was nice but the transfer case was pewtrid! Due to towing at close to gvwr I like the added fluid replacements given some differential failures on MLs recently.

On the rear and front differential I used Fuchs gear oil from euro parts San Diego.

Transfer case gets MB 134 ATF, and again its 12/liter at sprinter dealer as opposed to 17 at regular Benz car dealer

Anyone have a nice clear write-up for the Pre-BlueTec CDI filter change?

Krusty - did you do the transmission, diffs and transfer case yourself? What's the difficulty rating? Special tools needed? Local shop wants $550 for the transmission service alone.

I'm not too excited about trying to drop the pan on the GL without a lift - am I missing something?

PS - most recent Mercedes part number for the diesel filter on my GL is 6420905352. Picture of it is below. I see it on-line for $125. Like the idea of getting the equivalent sprinter part next time around - it's the exact same motor. To do the fuel filter service, you need the filter and two click clamps - parts 35, 60 and 100 in the diagram below.

I know from the parts department there are three different and incompatible diesel filters for the GL 350 depending on your build date - now that I've written down the part number for mine, I can find a more cost effective sourcing solution than taking the old one to the parts department the next time around...

For our 2011 GL350s there is two different filters. Mine uses the 5 pin plug (expensive one). Part number for 5 pin is A 6420904852. I pay 105 bucks. Also another cool add on is the extra port on the filter that has the cap (which changed from original one), you can add the water bleed hose off a sprinter that has a in line valve so you can drain water easy during the 20k intervals. Even though my sprinter is a Mercedes I find way cheaper prices at the Frieghtliner dealer as it is owned my MB and part numbers are the same.

Also i did the transmission and differentials myself. Not difficult, just somewhat time consuming. I put the GL in the garage on a Friday night, got up Saturday morning for a warm up and drained fluid. The only special tools are the same pump you used for brake flush (motive), trans pan adaptor and infra red thermometer. I ended up with 8.3 l flushed including torque converter. I did it all for about 150 bucks with OE fluid, filter, gasket and pan bolts (one time use magnesium bolts).

I totally enjoyed doing this taking my time, cleaning everything well and knowing torque converter was drained which dealer says is not necessary. I will post link of DIY I used also for reference on the 722 transmission.

You can use the motive pump to fill diffs also. Easy. I think since I tow heavy weight I am going to include this to my 20k interval.

Giving the GL some mechanical love, using my Hazet tools and hanging in the garage on a Saturday is as good as it gets for me, a needed diversion for busy work weeks.

Definitely interested in your DIY instructions... let me know once they are posted.

First of all thank you for the detailed post as I just did a complete service on my 2011 GL350 following your very instructions.

A few things I noted during the process are:

- I wasn't sure where to get the correct fuel filter and went with the lazy but more expensive way - Mann filter WK820/14 from dealership for $155 + tax.

- dealership has CLIC clamps for $1.50 each. I picked up 2 just in case. Did not need them in the end.

- my GL350 has a stabilization cross bar above the engine, had to remove it using E14 socket and 5/8 flat wrench. Flat wrench is necessary because sockets won't fit for one nut.

- I also had no choice but to remove a piece of firewall right on top of drivers side air box in order to take the box out.

- car did not start at first attempt, probably because fuel filter needs more time to get primed. Turned off, started again with no hesitation.

- both air filter and cabin filters are dirtier than what I imagined, surprisingly.

Air filters replacement on the om642 motor require reset of engine adaptations via Star/ das which among other things resets the air flow baselines.

Failure to do so will result in diminished performance as well as corrupt service requirement calculations

where is this done? I only see full service or pad replacement in the service menu?