rwolak

kajtek1

I think transfer case is consider lifetime filled, so this is personal decision to change oil.
722.6 Transmissions initially were "filled for life" as well, but later on MB changed the policy.
There are several levels of servicing those transmissions. The best IMHO is drain the fluid, wipe the pan clean, what is the most important part IMHO, let it drip overnight and refill with about 4l of ATF. Important part is new pilot bushing.

rwolak

The "conductor plate" issue on the 722.6 is caused from a seal leaking in the plug that connects between the conductor plate and ecm. If the seal leaks, oil has a tendency of being sucked up through the harness resulting of the tranny going into "limp mode". I was lucky enough to catch this problem yesterday on my 2003 CLk500 when I had the fluid changed.

Racin_fool

If there is fluid in a vehicle component, there should always be a way to change out the fluid at some point. At no point would I ever consider any fluid to last the lifetime of any vehicle. Fluid + moving parts = wear & potential leaks.
Yes I would change out the fluid or have someone change it for you.

kajtek1

My conclusion to "sealed for life" idea is that when the 722.6 was design back in early 1990's not too many cars would be on the road for 10 years and 100,000 miles was considered "retirement time" for most of the vehicles.
I think MB surprised itself with fact that those W210 are on the road 20 years later and some of them reached 1/2 million miles.
But anyway, seems they revised the idea and the converter drain plugs that were deleted about year 2000, come back in 2008.
Still lot of owners made 200,000 miles on factory ATF and seems the deteriorating orings on pilot bushing are often wrongly interpret for bad conductor plate or TCU.
Have to rub the deal I strike couple years ago on convertible SL500. The car was in limp and at 190,000 miles all shops wanted to replace the transmission.
Young seller got desperate and was asking $1500 for it. Since the car also had misfire on 1 cylinder, I bargained the price to $1300 and drove 26 miles home on 2nd gear.
Later the $10 pilot bushing, some ATF, new gasket/filter clear the transmission codes.
Replaced ignition coil, put new plugs and with new motor mounts the engine is so smooth, that you can put stacks of sockets on it and they will stay.
So when shops would take in the range of $5000, with some know-how and getting my hands dirty I was able to bring to perfection for less than $100

rwolak

konigstiger

Follow current 09 service sheet requiring both transmission & TC fluid be changed every 40000/4 years (whichever comes first).

kajtek1

There huge difference between "sealed for life" and "change ATF every 40k miles" so looks like MB engineers are eating their foot.
Still the manuals don't explain what is consider "oil change". Since some of those transmissions don't have converter plugs, you can only drain about 30% of oil in quick change.
Even the pan plug sits on high flange that will leave about 1/2 liter of dirt at the bottom. Than again, no mention about pilot bushing change, what seems to be crucial part of service.