my Yukon will shift fine manually,it wont take off automatically on 1999 GMC Yukon

we changed the rear end before the rearend went out it was shifting fine now if you put it in drive it wont take off but if you put it in low it will shift fine manually and pull good

Asked by for the 1999 GMC Yukon
Did you replace it after a rear end collision?
yes not a bad one though, it has been doing fine driving then the rear end locked up.Had it replaced now it acts like its slipping but if you take off in low then shift it to drive
it shifts fine