Gs3500

Hi everyone
my 08 gs350 awd is making a pop noise when I accelerate (even lightly). I can feel it pop again when I let off gas sometimes too. Not sure what could it be.... Any suggestions or next step would be appreciated!

Sodium

Have someone rev the engine while you have the hood open. May be able to get a better idea of where the noise is coming from, or if you don't hear the noise, that would suggest that the noise isn't coming from the engine.

ibidu1

iTrader: (1)

Is it the front or rear where the noise is coming from. Also you can roll down your windows to hear what kind of noise.

Gs3500

Seems to be in the front. It's definitely not the engine...
i think it may be the transfer case or differential.... It really only happens as soon as I hit the gas.... Maybe 50% of the time.

Gs3500

Could it be the awd system taking up some slack? Is this normal? It's quite faint but still audible.

ibidu1

iTrader: (1)

Maybe a bad transmission mount or a bad cv axle... Depends on where the sound is coming from. Take it to the dealer and have them inspect it

tayslexus

My guess'd be a CV axle as mentioned above

Gs3500

I think cv joints click especially when u turn.... Not when going straight

Sodium

Probably one of the engine mount brackets or insulators, or transmission mount like ibidu1 said. When engine load changes (stepping on or letting off gas), it will experience a change in torsional force, which means the loads experienced by the mountings and insulators will change, and metal can make noises from changes in applied load

Probably wouldn't be a bad idea to get it checked out in any case

Gs3500

Thanks for the suggestions. yes it is looking to be a mount. Today, I held the brakes firmly and reved the engine both in D and R. The sound sometimes would occur when the transmission engages without even revving. The rules out CV joints as well as loose brake pads!

Gs3500

Ok now it's happening only when stepping on gas. It is a single click as soon as I step on gas. Doesn't happen once the car is moving.... Only when starting from a dead stop. If I feather the throttle, the noise won't appear. Sometimes it will click (single click) again after I let go of the gas. This is starting to look like mounts. How would you really check them?

ibidu1

iTrader: (1)

Open the hood of the car and have someone in the driver seat with the engine running have that person put the car in drive and firmly holding the brakes, tap the gas and the engine will load up. You should be able to hear the sound and to where it is coming from

Gs3500

Turns out it was a loose axle nut!!! Just to provide everyone an update.

Gs3500

Torque those suckers down real tight! Fsm calls for 217lbft.

ibidu1

iTrader: (1)

Nice how did you manage to find it, or was a mechanic that found it?