Tires locking up on 2001 GMC Sierra 2500 HD

As I am driving there is a bang (maybe truck is trying to switch into 4wd) and all 4 tires are locking up. I put a new transfer case in last year. Any ideas?

Asked by for the 2001 GMC Sierra 2500 HD
1 answer
it is the Ebrake on rear end
mine just went out
it explodes,clean out pieces and you will have to replace a seal
I just went around it and still have 3 brakes working