Engine code P0708

Wife's 98 626 has CEL and runs fine until it gets warmed up. Then, it seems the tranny goes haywire and driving is almost impossible (I even had to drive it home once in Low gear). Two engine codes P0421 (O2 sensors?) and P0708 which I don't have a clue about. Appreciate any help/direction.

p0421 =catalyst effiecy below limit , needs to have pcm reprogramed at dealership. and the precat is probaly bad but do the repro first and make sure your tune up parts are really good and pray. secondly p0708 ?? I cant remember exactly but my guess without a book in frt of me is either a speed sensor code or some non sycronation code either way your car will more than likely need a transmission replacement.

Oh yeah the info I gave is specific for the 2.0L AT, am i right about those specs?