yes the steering box adjustment is, very critical. If you don't have the sector shaft exactly in the middle the adjustment will end up to tight, and hard expensive parts will wear.
The in pd measure is critical to keep from damaging the box. I only mess with them if the box is beyond hope, or have it on the bench. When doing a rebuild or doing a cross over conversion.
Tires can have a huge effect on steering. I am guessing the tires are new, since you mentioned they have little wear. Have the tire been sitting in one spot for a long period ? Wheel bearings, and Alignment. Lifted trucks loose positive caster. positive caster adds stability at higher speeds. A 4" lift isn't normally to detrimental to caster, but the blazers short wheel base doesn't help. Toe setting can change how the truck handles, toe'd out vs toe'd in. 1/8th" toe in for 33's is pretty close to what you need, any more and just wearing tires badly. Bigger tires are less effected by small toe adjustments. Toe out is bad, can cause wander.
front axle u joints can be sticky, causing a hard spot while turning, I think I see auto locking hubs. These hubs may or may not unlock when they're supposed to. Jack the front axle, rear tires chocked, jack stands under front axle, spin tire while watching the axle at the knuckle, if it doesn't spin hubs are unlocked, if it spins your hubs need attention. While you have up check the ball joints, I use a long bar under the tire and try to pry straight up while watching the ball joints for up down movement.
The in pd measure is critical to keep from damaging the box. I only mess with them if the box is beyond hope, or have it on the bench. When doing a rebuild or doing a cross over conversion.
Tires can have a huge effect on steering. I am guessing the tires are new, since you mentioned they have little wear. Have the tire been sitting in one spot for a long period ? Wheel bearings, and Alignment. Lifted trucks loose positive caster. positive caster adds stability at higher speeds. A 4" lift isn't normally to detrimental to caster, but the blazers short wheel base doesn't help. Toe setting can change how the truck handles, toe'd out vs toe'd in. 1/8th" toe in for 33's is pretty close to what you need, any more and just wearing tires badly. Bigger tires are less effected by small toe adjustments. Toe out is bad, can cause wander.
front axle u joints can be sticky, causing a hard spot while turning, I think I see auto locking hubs. These hubs may or may not unlock when they're supposed to. Jack the front axle, rear tires chocked, jack stands under front axle, spin tire while watching the axle at the knuckle, if it doesn't spin hubs are unlocked, if it spins your hubs need attention. While you have up check the ball joints, I use a long bar under the tire and try to pry straight up while watching the ball joints for up down movement.
