The pins and springs have nothing to do with the force on the side gears when the axles are under power. That force is provided by the crossshaft pushing against the locker. The pins limit relative movement between the two halves so the faster turning alxe doesn't try to relock (as if the Jeep were in reverse), but have to allow enough movement to allow disengagement. That's why spacing is critical. The springs keep the teeth engaged as much as possible while one axle is unlocked (causing the normal ratcheting noise)to lessen free play when force is reapplied, thereby keeping the teeth from slamming together more often than they normally do when they make an occasional Loud (yet normal) Bang, as they are prone to do. Stronger springs would just result in a louder ratcheting noise, not more force on the teeth when driven. I do believe there is something wrong either with the install or the locker but not the springs per se.
Just my opinion of course. <img src="/forums/images/graemlins/cheers.gif" alt="" />