Transmission

Hello

I have a problem with my gearbox so it seems to me that I have 6 to 7 gears but I can't.

I'll describe it as it is.

So the first thing I do when I'm driving on M and the first gear in there is howl the gear is but only the first. So when I drive normally when the gear turns on then the speed meter falls by about 400 u/min then it takes one piece then the gear is right. The whole thing usually only happens from the first to the third. The fourth course is normal. The whole thing is when I turn down the kickdown he usually does normal then when it's so far to switch he turns back on only the 400U/min and then the gearbox has no more power it seems like someone holds you. So gear oil I have changed filter also oilstand ok 1000 times checked. There are no errors in the memory. Who can help me or is this thing broken?

mfg
Michael