It's just frustrating. I agree - Lifetime just doesn't sound right and I too, can't believe it's in the Maintenance Manual as that.
My CLK 430 has 113k now, but I never drive it like a crazy race car or anything - I take good care. It shifts perfectly, drives really well and I do think it's the original fluid (I'm the 2nd owner..a grandma had it prior)
My hesitation on replacement isn't the 200.00$ it will cost, it's:
A) How do I KNOW the mechanic actually does replace it?
B) I hear sometimes things happen after fluid changes like this - that it actually made the car worse, even ruined the trans.
Note I do have a great indy mechanic...not merc specialist, but he knows his stuff. He said I can do the trans fluid change soon, but there's not any urgent need for me to rush into doing it.
Come to think of this, but why is there no "Power steering fluid replacement" recommendations in the manuals.
For brake fluid - I guess I will get to that eventually! (and coolant if needed)
I have just over the years, come to change my "take" on car maintenance; I had mustangs, Saab 9-3, a CLK 320 for a while, etc and I always followed the manual exactly...and I just think a lot of the work was unnecessary in the long run.
I have a 2009 ML 350, and I have followed the manual exactly, because I don't want the dealer to meiser themselves out of honoring my warranty, should they not have indication I've maintained to spec. But once the warranty ends in 2015 (I have the extended bumper to bumper on this car) I will likely not be so anul.
I think there are tons of Merc owners out there, still driving their late 90's or early 00 vehicles, who don't interact on these sites, have never replaced things like trans fluid, and go on their merry way in the cars for a very long time. (I live in SOCAL and I must say...there are still SO SO many late 90's and early 00's E and CLK classes on the road it's crazy; made me see that mercs do last long and I'll bet many of these people only worry about oil changes and maybe some filters.
I think because I've been a motorcycle sportsman (road racing) since the early 80's and always done my own maintenance and repairs I know that frequent oil changes with top quality oil makes for problem free machinery.
With my expensive Mercedes cars it's just cheap insurance to use top quality fluids and change often. I do the engine + filter yearly, brake fluid yearly and now that I've done the research and successfully done the 7GTronic 722.902 service ... I'll do that every 3/4 years. It only cost me $AUD105 to do my transmission plus half a day of my time. That was for the ATF, pan gasket and filter. The dealer quoted me $AUD900. I asked if they flushed the oil cooler of the old fluid. He hesitated ... because he didn't know ... and then said "oh yes, that's part of the process when they drain the oil pan it drains the oil cooler".
He was just spruiking BS because he'd never been asked before. They must think every caller is a complete mechanical half wit so they tell them anything.
So my frustrations come from trying to have a sensible intelligent conversation with the MB dealers. You get a different opinion every time you speak to them and if you start asking more detailed questions they start making things up on the run. The guys out the back doing the work are no special technicians. Most of the time we end up with a 16 year old apprentice doing the work.
I spoke to two different dealers on different days about the "filled for life" 722.682 5GTronic on my Vito and got about 4 different answers as to what that meant ... from never touch it to change every 4 years.
You mentioned you've had Mustangs. Ford Australia are ceasing production of cars in 2016. They've mentioned they're doing the market research on bringing the Mustang to us. Are they any good? When I was last in the USA I noticed you could get V6 or V8 versions.