If this is a 'change it hot and change it often' question, I think we need Larry Bible to answer this.

I have two points to add to the discussion.

First, Ken300D suggested cleaning the parts under (or is that above?) the pan when you have the pan off. I have consistently heard over the years that the pan internals should not be touched, no matter how tempted you may be, when the pan is off during a change. The filter is removed and replaced and the pan is put back on without touching anything. This is because you're more likely to introduce lint or dirt with the wiping than you are to remove grime if the tranny is seeing regular service intervals. I would therefore recommend not wiping the internals when the pan is off.

Second, for those that are both anal retentive AND obsessive compulsive, if you drop the pan, drain the TC, and break the fittings on the tranny cooler, you can get just about all of the fluid in an MB tranny. I'm usually content to know I got the TC and the pan.

HTH, not trying to start any wars,

someguyfromMaryland

Ren,

Here are a couple of previous posts that should help.

MB Approved Trans fluid (list is about 2 years old, but you can always call MBUSA and ask for the "Factory Approved Service Products S-0473-00M"): http://www.peachparts.com/shopforum/tech-help/10583-best-atf-mbs-synethietics.html?highlight=transmission

One poster's experience and thoughts from his mechanic are located here: http://www.peachparts.com/shopforum/tech-help/29150-transmission-filter-life-expectancy.html?highlight=transmission

Thick ATF?
 

400E,

Almost daily, I find another reason why I like living in the Southwest. I have to ask, does ATF fluid actually get thick up there in the winter?

I have a very early recollection of Shickley, Nebraska, southeast of Omaha, in the early '40s, where my great-grandmother's water pump bucket in her back yard had a skim of ice in June, but to me, thick ATF conjures up a vision of 'molasses in January'.

Realneal,

Yep, ATF seems to thicken up like molasses in January up here. When the ambient temp hovers around 10F all day, and I start up my beast for the commute home, the tranny not only takes another second or so to engage when you put it in gear, but even then, when you first apply some throttle, there's a very noticable delay before the vehicle actually moves. These changes seem to improve (though are still noticable) since the switch to Mobil 1. Does it translate to less wear/longer transmission life? Don't know (yet) but I figure it's worthwhile to stack the deck in my favor.

Steve