While chasing down Kajtek1's homebrew ATF dipstick for a 722.6 tranny, I came across a testy thread about MB fluids. There were those that took the position that MB's are a breed apart and we'd better use what MB sez or we'll have exploding cars all over the place. And there those (Kajtek1) who said that they found little difference in using other quality fluids, so why spend the outrageous amounts of money on fluids that appear to be no different than MB fluids in service.
I just gotta throw in my $.02.
When I first bought my '97 C280 new, I assumed the position
in front of the MBZ altar to preserve my warranty. But after I blew through 50K miles and started doing my own work, I began using other fluids than MB recommended products.
The 7500 mile oil change interval on a hot running engine was a joke, thought up by the MBZ Engine Division Job Security Commission. So I reasoned that if I was changing oil at 3-4K intervals, I could use Walmart oil and that's what I have used. The oil filters used to be Purolator cheapos because the premium Purolators cost 4 bucks more and by Purolator's admission were the same part. Pep Boys moved out of town taking my oil filters with them, but NAPA still supplys me. When I change engine coolant, I use NAPA brand.
When I inquired of MBZ about the ATF change intervals and was told that it's a "lifetime" fluid. I thought Cool! But I painfully discovered that it meant zilch because when the "lifetime" of the oil was up my transmission coughed some sort of valve body that cost $1400 to fix and MBZ Dealer said that the transmissions were only good for about 150K. That was at 140K miles. I wasn't spending $5K for a new one so I said fix it. I talked to transmission mechanics and they all said 50K intervals max. I use an ATF by Febi. The last change (295K)shows ZERO metal in the filter and the tranny is smooth as silk.
I replaced the water pump with an aftermarket part at 229K, the aftermarket AC compressor @ 240K. I did my own valve job at 256K, (local automotive machine shop) only because the head gasket blew. At the time I was still getting 25-27mpg @ 75mph and burning no oil. The car has 295K now and runs like a top, leaks some oil, but burns none.
Over the life (not done yet) of the car I've saved a ton of money by buying aftermarket parts and fluids. I've come to the conclusion that the MB is a well designed piece of machinery and a well designed machine doesn't implode because of the oil level being a millimeter or two off ideal (my wife has over filled it and run it off the dipstick) or its oil coming from Walmart, or its oil filter coming from Purolator, via India, or it's water pump coming from China. When car manufacturers ($) and enthusiasts (status) get into the discussion, the sky starts falling. But as long as the bean counters at MBZ recognize the economies of OEM contractors in this competitive global world, we (car buyers) can be relatively assured of lots of compatibility and competitive pricing from the aftermarket. And my experience is a good car doesn't blow up if reasonable quality stuff is fed to it or bolted to it.
Your mileage may vary