I have 2004 Tahoe and it makes a groaning noise when make left turn at slow speed with my foot not on gas. took it shop and they said to power flush with synthetic. I did that and it went away for awhile but it,s back. Has anybody else had this and what might be the fix

 

sounds like it may have had some comtamination at some point and the symtoms have returned but the damage already has been done or the flush didnt get it all i would try again especialy if you have the hydra boost assist it has an accumilator and if the brakes weren't applied during the flush you might have residual contamination still in the system give it a try