did whaddon and abused it drive home and it was fine, drove this morning on the motorway and its not shifting into top gear. tried shifting through 1 2 3 D but that didnt help either, the exhuast is blowing badly at the manifold or down pipe quite badly now, are there ay quick things to check here? is there a kick down cable/wire, vaccum etc etc that i can check out? otherwise around town she drives sweet as, its just evident on the motorway

any ideas please/??????