I have been working on a 2006 h3 first it was just to change the shift solenoid out then after inspecting the pan the transmission was toast there was metal and tranny fluid was black and burnt.there was a high rev after 35mph so the owner bought another transmission to be installed so I installed the transmission everything went on smooth but after all said and done started it up let it warm up and then attempted to shift in reverse ...nothing. Drive ...nothing all gears no shift at all..so we went over again with a fine tooth comb lol attemted again to no surprise still no shift in any form ..what can it be ?fluids are on spot ..

 

did you reuse the torque converter?

 

No not the same one from the old tranny we used the one from the transmission he bought.

 

then maybe the replacement transmission has a failed pump. you might have to check the line pressures.

 

Is your Transfer Case in Neutral? Simple things first.