The external range switch is no problem and the 01 GTP trans uses this also so if it is not on the trans you got then simply swap over the one from your existing transmission. The switch is bolted to the trans case just below the shift lever and is black in color and has two electrical connectors on it.
For cooler lines you will either have to use the quick connect lines that match the trans OR get the correct thread-in type feed fitting to work in the 01 case and you can use your existing return line fitting from your 98 case. There is a cooler fitting thread that is stickied at the top of the trans section that explains the differences.
