question on a 2001 transmisson going in a 98

physically it should bolt up ok, but i belive your car still has the actual speedo gear installed in it whereas the newer transmisisons from 99-up have a magnet on the tailshaft to tell the sensor what is going on. i had a friedn who did the same thing installing one out opf anewer car in his 98 and it worked fine, but his speedo didnt work right