gearbox valve body

Hi , I have saab 95 model 2002, vector V6 3.0L gasoline engine. I experience a slam in the gear when i change into Reverse, and when i put 'D' it slams a bit and you notice delay in engaging.. and looks like it goes in 3rd gear.. so I have to put in 'L' to get first gear them shift between gears .. it would also slam when shift out to L to 2 .. so looks like have an issue with the 1st gear.. took it to the deal.. they mentioned i am getting error code P0748 and P0780 .. and need Gear box Valve body changed .. found it quite strange that at such a low mileage 83000 KM i get this problem.. Anyone experienced this before? Do i really need to change the whole Valve body .. and i am being quoted $ 2000 for it.

Thanks