95 chevy 1500 lifted 4 inches

[fred71]

the truck is a 1500 extcab with a5.7 liter motor. lifted 4 inches ,this is asuspension lift. when i put it in four high,and go the speed of about 40 to 50 then let off the gas i get some sort of vibration noise. then if i push back on the gas again it does it again. note it only does it at speeds higher than 40 when letting off the gas and applying the gas.this truck is lifted 4 inches could this be my front drive line making this noise. i ve went thru the transfercase and the front diff,it all looked well. and it only does it in four wheel drive please if there is someone out there who can clue me in please send me an email soon thank.