2003 s10 4 wheel drive problems

Its a automatic transmission with a v6 4.3 vortec. The front axle will not engage, it is not the acuator (I replaced it and the cable) you can pull the cable and the axle will engage. There is a low buzzing noise(coming from the drivers side) until you give it gas. This noise stops when the front axle is engaged. The transfer case will go from hi to low without any problems.

Its a automatic transmission with a v6 4.3 vortec. The front axle will not engage, it is not the acuator (I replaced it and the cable) you can pull the cable and the axle will engage. There is a low buzzing noise(coming from the drivers side) until you give it gas. This noise stops when the front axle is engaged. The transfer case will go from hi to low without any problems.

Could the low buzzing be a vacumn leak.
Try to pinpoint the area of noise and what kind of noise.