Knocking in the front driver side wheel - 2008 Cadillac CTS 3.6L

depending on when knocking is heard could be all sorts of dangerous things. If while turning, could be control arm bushing failing, would not change much with speed, but would with poorer road conditions. (danger wheel doesn't follow steering, crash)

If follows speed of wheels, could be a bad bearing in the wheel... (danger, one wheel stops spinning, crash) If bearing, change in pairs on the axles (so both front at same time) as if one goes, the other is as old...

Both of these "could" be missed depending on severity if on a lift, as the wheels would not be under load...

have mechanic go for a drive with you, so you can demonstrate the problem. If they won't, go to another mechanic.

Also loud knocking... could be engine... if follows RPM of engine, aka you can make the knocking while vehicle is still. (danger - engine siezes, crash)

Loud knocking could be a shock (strut) mount having broken, or shock spring...

you need to give more detail as to when sound occurs and in what circumstances. I've given you some things to try... good luck!

Wheel bearing end of story ,sometimes this happens ? did you knock them in with a big hammer or were they pressed in ?

First check wheel bearing. Jack front end up lifting tires off ground and see if the wheel moves by pulling on the sidewall part of wheel from top and pushing bottom towards the car does this back and forth if there is play, wheel bearing could need replaced. Take tire off and check for loose brakes, loose calipers, loose dust shields , etc. everything except rotor should be tight.

go to your nearest service stations and have your suspensions go for GREASING.

sounds like wheel bearing, jack wheel up, an see if there is any free play, by trying to move wheel side to side

See if you can bounce car and replicate the noise. If you can, you should be able to find it, and put your hand on it. Stabilizer bushing are a place to look, both at the lower a arm and on the frame. If you narrow it down to the strut, it will need to be replaced. The front trans mount also goes bad, try putting it in drive with your foot on the brake and give it some gas and see if the engine moves an excessive amount.

Iside the front fender on the driver side, Plastic cover ahead of the front tire and its up in there. There is an airbag senser in there too don't knock it hard or you'll set off the airbag.

it sounds like you have a bad cv axle on the drivers side.

Front wheel drive cars have CV joints in the axles to permit the wheel to turn for steering. The CV joint is basically a universal joint on steroids. When they ware out it can cause this type of condition.

I think your right, CV joint