7G Auto starting to fail ?

[Nagoya]

Hi,

I recently bought a 2008 m 4matic 320cdi with the 7G.
It has just started sending slight vibrations through the steering wheel and floor plate in each gear, I can also hear a igjt humming when this happens.
It is still under mb warranty and the dealer has acknowledged that some noise is coming from the gearbox or the transfer box.
I am convinced a bearing is starting to fail in the drive train
The dealer has said that they will change the oil In Both the units to see If it resolves the problem.
Should I be concerned that if it does resolve it short term, the problem will not be cured and it may then be out of it's warranty ?
The car is from the MB approved used programme which provides for a 12 month warranty or a 30 day vehicle exchange warranty, which is still valid.
Should i send it back ?
Please offer your wisdom and advice as I can not enjoy a 40k car that has this question mark over it.

Thanks..

 

[kwakdonut]

Push hard and don't take 'No' for an answer. If you are not happy, then push for a new gearbox

 

[st4]

Just send it back, 30 day cooling off period ideal. Find another.

 

[Mudster]

At that age it will still be under warranty...get is back pronto.