I have a 99 CTD with a built tranny triple disc etc... my question is that. i just drove an 01 with a built trans and the truck locked up in 3rd gear with out the tow haul button on. my truck only locks in 4th gear overdrive and when i push the tow haul button? is this normal for my year or truck? or did my computer take a dump? also im starting to get a dead spot in the throttle sensor. could that cause it?