05 z71 issues
 

I have a 2005 ext cab z71. the abs light is on and the ebrake light is on. and my 4x4 does not work right. when you put it in high and take off its like the back wheels are not wanting to spin. as fast or not at all. the speedometer is off 15 miles an hour. it same when it is in low. is push button 4x4. I need major help. what is my issue?? help?????? someone????????