2008 with electric rear locker help!!!

sometimes when i go to back out of the drive the rear wheel i think its just the left is locked solid like the brake is on, as i keep trying it will pop and then roll,,, ok i have checked ebrbake its all good, i have removed the hub and the brake parts are all nice and clean and working as the should, is theere a problem internal with the rear diffs? fluid is clean and full, 124 xxx on truck its always babied... it seems to only be the drivers rear that locks,, i can push the gas hard and the other tire will pull and skid the drivers rear ,then it might just release with a pop or it might not make a noise at all

 

Was the e-brake on prior to this happening?

 

i had the very same thought that maybe the ebrake wasnt releasing,, but i looked and did it several times, with and without the brake,and when i took the axle out and inspected the shoe and hardware ,, allwas normal,