Hello, Bought this car last year without enough due diligence and now I'm paying the price. The AT shifted buttery smooth until it stopped up-shifting out of 1st. The indicator lights that show when it is in Sport or Normal mode are blank when the shifting stops working. I had bought an expensive battery to move it around while I did the t'shooting and repairs. It's an inexpensive battery which drains after 3 or 4 days if we don't start it or charge it frequently. I was wondering if installing the correct battery would fix the shifting problem? The car really comes alive electronically when I charge the battery for a couple of days and everything seems to work: Navigation, Cruise Control, and all the other electronic goodies which don't usually work. But all the electronics drain the battery (too small) and we lose all that stuff.

I wasn't making the connection between the amount of charge and the AT's functioning until recently.

Any ideas if I might be right?
TIA,
Larry
2006 MB E350 AWD