FrostedLogic

I recently purchased a Mercedes S550 4matic (2007), I am having a transmission issue where I am able to shift into gear for the first few seconds at startup, however, it slips out of gear into neutral despite appearing to be in drive on the dash. I also believe that my vehicle is draining my vehicle's battery at a rapid rate, the previous owner had "allegedly" changed both the starter battery and main power battery a year ago, when I received the vehicle I had to change both batteries again. After awhile, the vehicle drained the rear battery completely I took it to partsource (Autozone for Americans) to get it tested and charged, however the machine came up with a "recommendation to change" This has happened for the past 3 times I've taken different batteries to partsource. Could anyone provide some feedback on what may be causing the electrical drain and the transmission slippage?

BOTUS

the gearbox might be worn out and needs a rebuild - you don't mention the miles... but basically anything after 60k is a risk if the car stuck to the original service schedule of never change the fluid till it dies

the issues come about because the box is such a pile of junk that they were self destructing so fast they had to rush out one off change at 42k miles to try and get the swarf out - but many garages and owners never noticed - of course the boxes still fell to bits mainly driven by "it would be a disgrace if it were a Chinese electroplate" failures - so they decided on changes of fluid every 36lk miles ongoing

if its running on swarf and treacle - you might get lucky with new solenoids and fluid change - but even so expect an electroplate $1200 an ISM $1300 and a TC ($2400) within 2 years....

as for the battery drain that's normal drive the car or buy batteries

oh dear - I see its a 4x4 - even more fun and expense - there was a bearing made of chocolate and USA should have got a free gearbox elsewhere in the world owners got a little easter egg of a 9k bill

FrostedLogic

Im at 176,956 KM (Metric) aprox. 110,000 Miles, this car has an extensive ownership change, however one of the owners was the Mercedes dealership so i'm hoping that I was able to get a full service from them