4wd engagement leads to pulling to the right

[Schurkey]

Stopping one wheel is no big deal. The differential is "open" so one wheel can spin if the other is stopped.

Stopping BOTH wheels is a big deal. Something's broken.

When that happened with my Trailblazer, it was the transfer case--stopping the wheels also stopped the driveshaft.

 

[Nad_Yvalhosert]

I'm gonna offer a different view: alignment.

Wrong wheel drive vehicles require an equal caster angle to eliminate a steering/acceleration pull. They use camber to correct any irregularities.
There's also another usually unmeasured angle called axle setback (similar to thrust angle). Both of these angles, if not compensated for, will cause a pull in 4x4, but not as much in 4x2.

Perhaps your truck needs a more rigorous shakedown and alignment? Considering the changes that the additional lift brackets, increased track width, SAI differences, etc that the "rough country 6in on some crappy 36in tires atm." have made?

Lastly, tire condition is important. Uneven tread wear, tire inflation, or an internal rubber defect may cause a pull. Have you tried cross rotating the fronts and see if the pull changes direction?

 

[Hipster]

I'm gonna offer a different view: alignment.

Wrong wheel drive vehicles require an equal caster angle to eliminate a steering/acceleration pull. They use camber to correct any irregularities.
There's also another usually unmeasured angle called axle setback (similar to thrust angle). Both of these angles, if not compensated for, will cause a pull in 4x4, but not as much in 4x2.

Perhaps your truck needs a more rigorous shakedown and alignment? Considering the changes that the additional lift brackets, increased track width, SAI differences, etc that the "rough country 6in on some crappy 36in tires atm." have made?

Lastly, tire condition is important. Uneven tread wear, tire inflation, or an internal rubber defect may cause a pull. Have you tried cross rotating the fronts and see if the pull changes direction?

^^This, powering up the front will amplify alignment issues, ill worn, cupped, internally separated belt will do same, spot on info above. probably both issues.

 

[Schurkey]

Wrong wheel drive vehicles require an equal caster angle to eliminate a steering/acceleration pull. They use camber to correct any irregularities.

Well. I learned something today.

A thousand years ago--when FWD was rare--I was taught that road-crown could be compensated-for by approx. 1/4 degree of camber spread, or up to twice that much (1/2 degree) caster spread.