I've noticed since I had new front and rear shocks put on my Durango that when I pull in the garage I can hear a whistling noise until I put the truck in park. That is the only time I am hearing it what could it be

Hello, 

Thank you for writing in. It is typical to hear sounds from our vehicles that we don't normally hear when it is in an enclosed space like a garage or alley way. The sound waves bounce off the walls and we are able to hear more of the noises we may miss driving down the street. That being said, you are going to have to do some further testing to try and pinpoint when the whistling occurs. Doing so in your garage may be the best option. 

It sounds like the whistling is being caused by the drivetrain. To verify this, keep the vehicle in park with the brake on and rev the engine to 2,000 RPMs for a few seconds. If you do not hear the noise, then the whistling is likely not coming from the engine. You can then focus on the drivetrain. Take the brake off, put the car in reverse and listen carefully for the sound as you back out of the garage. Then pull back into the garage like you normally would, and verify that it is the only time you hear the whistling noise. You will then need to inspect the drivetrain components, and may want to seek professional help if nothing is obviously wrong. 

The drivetrain consists of the transmission, differential, axles, drive shaft, CV joints, and the wheels. While replacing the shocks should not have directly effected these components, something may have happened during the repair that is in fact causing the noise. Only further testing will tell. Good luck!