99 Leganza code P1780 For auto tranny

[jjthegreat]

Hey guys, my first post but ive been on this forum for years now.
Just bought a 99 Leganza CDX for REALLY cheap because the previous owner didnt want to bother with a transmission problem. It works on 1st gear when u put it in L but will not shift into second. When you put it in 3 or D, it goes straight to 4th. Heres the kicker, when you put it in 3 or D, it STARTS in 4th. Cant lug your way to speed with that one. So for now i shift it like a manual with only 2 gears. The HOLD switch is not stuck, plus it wouldnt cause that situation.
Anyways, my question is the following:
Got the reader, and got Code P1780: Transmission Control Switch Out Of Range
What the hell is that? This is the gear selector on the transmission itself? Is this broken part replacable, or it is just better to replace the tranny alltogether.
I know the 4T40E is used on a lot of GM applications, but I took a look at the tranny from a 99 sunfire GT, and does NOT look the same tranny on the leganza even if they are both supposed to be the same transmission models.
Are the auto trannies from the lanos and the nubira the exact same? Can I go to a u pull it and steal it from one of those? Or can I just take a tranny from a trashed malibu and use that?

[woo]

i know the auto in my 98 leganza 2L is a ZF, the same as is in the peugeot 405. Dunno about what is is the 99 model

[jjthegreat]

Oh well.
Bought another leganza that has no problems.
Apparantly, in america, the legaza uses the d20 transmission which is found in the nubira as well.