Dan Rants! Geez, you've been so "understated" lately, I was wondering when we were going to get a little rant. And it was just a little rant...
Gilly, I agree. That said, I'm not sure who to believe some days. The conflicting info I hear isn't from I-might-know-something folks, but from real Mercedes employees.
I don't think I'm saving the tranny from catastrophic failure, but perhaps just extending it's total service life with occasional fluid/filter changes. I can't recall any autobox that calved due to dirty fluid. They just wear out a bit faster. This might be different in the 722.6, but maybe not. Recall that MB thought 20,000 oil change intervals with dino oil in early FSS cars was peachy.
I know that "do-gooders" are a common failure reason with automatic trannies. The Lubex kid "tops off" your tranny fluid, and presto, it's headed for an early grave. I understand MB deleted the dipstick on the 722.6 for just this reason. Keep well-intentioned oil-change-service idiots from changing the fluid level willy-nilly, and as a side-effect keep "cautious" owners from doing the same.
Now that I've had my car for more than a few years, and more than a few miles, I have to admit to loving the 722.6. The "adapting" part of seems to work better than I ever thought it would. The shifts are still smooth. The ratios seem well suited to the car, and having the fifth gear makes all the difference to me. Heck, it even holds the gear when I brake hard for a corner, instead of upshifting and dropping the revs right out of the torque plateau. That's great!
Heck, life could be worse. I could be saddled with a Dodge product, with the "replace every spring" autobox. Or perhaps the infamous ZF box built for BMW whose front pump didn't run at idle. 100K-miles is the outside life for those boxes. Acura put tons of bad five speed autoboxes in the TL, and had a WAY higher failure rate than Mercedes. Honda products got some bad sluch-boxes too. Mighty Honda!
People point to GM and tell me that is HOW to make autoboxes. Remember the TH400 and TH350? Yup. Good boxes, but not without their own problems. Besides, they were primitive beasts. Anyone recall GM's first four-speed boxes that didn't seem to last all the way home from the showroom?
Ford sold Mazda boatloads of four speed boxes that were shipped to Mazda for use in four banger 626's in the mid 1990's. They don't last much more than 30K-miles! Warranty? Fight for it if you're lucky.
I feel the 722.6 is a great design, and there probably have been some production faults that are not design related, but they seem to be worked out. How many of these five-speed boxes have they shipped since MY1997? Wow.
1998 C230 "Black Betty"