You need a torsion key.. most mechanics can twist the bar for cheap
Yes you can Adjust the torsion bar to raise it. I did this on my 1 ton Chevy to raise the front end. I had an alignment right after and it has worked great ever since.
Under vehicle by end of torsion bar (side closer to rear of vehicle) there should be a 6-point bolt which when tightened or loosened will apply more or less tension to torsion bar.
on the new body style 1500 trucks there is no torsion bar. there is now a coil over suspension. to raise it and level the truck you will need a "leveling kit" typically comprised of a metal spacer that will sit above the coil over.
Good info about raising front end by adjusting torsion bars.www.duramaxforum.com/forum/04-5-05-lly-performance-parts-discussion/4491-torsion-bar-adjustment.html
Take the truck to your local Chevy dealer and have them adjust the torsion bars to lift the front and then do a realignment. About 100 bucks. New torsion bar keys are not needed.
There is a bolt near rear of torsion bar (the end closer to rear bumper) which will increase or decrease the tension on torsion bar when you adjust bolt.
Under vehicle, by end of torsion bar not attached to control arm.
The Torsion bar is a suspension component. It essentially "twists" ever so slightly to adjust ride height. This is adjusted by a special tool specific to the manufacturer.
torsion bars only exist on 4WD dakotas....2WD have coils
go to this website www.planetisuzoo.com and slowly scroll down to Isuzu Torsion bar adjustment that is where you should find your answer to this question.
as the rear is torsion it is not straight forward. the torsion bars have to be removed one side at a time, with the torsion bar out simply adjust hub the required amount and replace torsion bar. then do the other side. this can be hard as the bars can be difficult to remove. best left to professional should cost between £60-£100
You remove the metal retaining clips on the back side of the frame / cross member that stop the torsion bar from sliding out. Figure out a way to clamp something to the torsion bar and smack it with a hammer driving the torsion bar towards the rear of the car. PS they do sell tools made to clamp on to the torsion bar. I would also suggest having the wheels off the ground and hanging. Also loosen the nut that adjust the ride height.