i have had the loud pop as well pull the axle shift motor and check out the fork and sleeve and make sure that the collar moves freely if it does then your fine there take the motor and bang it against the part with the vacuum ports against something and watch dirt and rust fall out. it fixed myn.
94 yj, 4" procomp lift, 3" body lift, sliders, cshr corners, d44 e locker rear swap, 35" bfg at's, 4.10 gears, crown 7 layer brake lines, jks discos, jks track bar disco, 97cherokee 4.0 swap.
next up twizted soa full widths. 14bolt and dana44
colorado, home of the insane