Thanks for you thoughts Gilly,

I never gave any thought to the idea that the number of quarts in the engine should have a direct bearing on the number of miles between drains.
1 quart = 1000 miles, does equate to around 8000-8500 per change.

And no, we probably will not try to go 250 K, but my wife is figuring on driving it at least another 50-75K before trading it off.

The one comment about the GM version of the FSS was interesting.

We do have a new GM with their new milege computer on it that gives you a percentage of miles used on the current oil change. I only have 800 miles on it so I have not history to discuss at this point. It has regular oil in it and I have not decided if I'll switch it over to synthetic yet.

Gilly, whats the thinking on the transmission fluid and filter on the ML. I've never towed anything with it so it has not had any hard use. just my wife and myself and she'll only 5 foot!

On the Diesels, the service manager always told me not to change it if it smells good and looks clean becasue of the possibility of getting small particules of dirt into the valve body and causing problems. I don't think I ever had transmission service preformed on the 7 Diesels I owned.

Gary in Ohio