Originally Posted by Onebadtruck
what is the point in of doing a TC lockup.
Realistically,it is for testing purposes,thats about it. Anyone using it for anything else without a controller,will forget it on and end up trashing there trans.When used properly with a controller,it helps give engine braking and keeps the tc locked when wanted, if the trans is built to take it,with billet parts,and good tc,and internals,it can be good,as it provides 100% power transfer when locked.
It is also used by guys who got enough money to mod the motor,but are too cheap to buy a good torque convertor and trans,and try to get by by locking the stock TC to accelerate quicker.They quickly fry the lockup out of the tc,and forget it on as well,trashing 3rd gear and a few other parts.
On a 2001,there is no reason to lock the tc manually,as it locks in 3rd from the factory at WOT,and stays locked while it shifts to OD.The 99 and older trucks would not lock WOT until almost wound out in OD,or until OD off was selected,then it would unlock to shift to 4th,and relock when OD was turned off.