S
Saabstory88
Guest
I have been trying to diagnose a noise on my 55k mi 2018 Mid Range. It has been becoming more apparent over the past 3 or 4 months. Today, I was able to finally get around to checking the torque on the rear suspension components. I also made sure to clear all debris from the aerodynamics. The noise is still apparent, so I spent an hour or two driving around to eliminate variables and get a clearer picture of when the noise occurs.
The sound has the dynamics of something becoming loaded and unloaded, as opposed to a noise with a consistent volume and frequency across the range of motion. It is reminiscent of a squeaking floorboard, and seems to be localized to the rear of the car. This is true both with windows up and down. I can not reproduce the sound under static conditions, such as applying my full weight weight, or applying shifting weight (bouncing on it) to each of the door sills as well as the trunk sill. The noise occurs when accelerating. The noise is present as the motor provides torque, then disappears as the torque loading stabilizes. It makes an additional creak as the motor torque is unloaded. The sound is not present under any acceleration in reverse. It also does not occur under light or heavy mechanical braking, as well as not during regen. It does not occur over speed bumps or on rough roads. The noise does occur when cornering and holding power constant, but does not occur when cornering in neutral. I have repeated each of these scenarios several times, and the behavior is completely consistent.
Based in this, it leads me to believe that I need to be looking at Subframe torque and lubrication. I imagine that this sound would occur in only the observed conditions if say, one or both of the rear two subframe bolts was loose, or the mating surface was not properly lubricated. If that fails, perhaps even the half shafts? Do these seem like the best next steps? Has anyone had these very specific symptoms (not just general rear suspension noise) corrected under warranty? What was the correction?
The sound has the dynamics of something becoming loaded and unloaded, as opposed to a noise with a consistent volume and frequency across the range of motion. It is reminiscent of a squeaking floorboard, and seems to be localized to the rear of the car. This is true both with windows up and down. I can not reproduce the sound under static conditions, such as applying my full weight weight, or applying shifting weight (bouncing on it) to each of the door sills as well as the trunk sill. The noise occurs when accelerating. The noise is present as the motor provides torque, then disappears as the torque loading stabilizes. It makes an additional creak as the motor torque is unloaded. The sound is not present under any acceleration in reverse. It also does not occur under light or heavy mechanical braking, as well as not during regen. It does not occur over speed bumps or on rough roads. The noise does occur when cornering and holding power constant, but does not occur when cornering in neutral. I have repeated each of these scenarios several times, and the behavior is completely consistent.
Based in this, it leads me to believe that I need to be looking at Subframe torque and lubrication. I imagine that this sound would occur in only the observed conditions if say, one or both of the rear two subframe bolts was loose, or the mating surface was not properly lubricated. If that fails, perhaps even the half shafts? Do these seem like the best next steps? Has anyone had these very specific symptoms (not just general rear suspension noise) corrected under warranty? What was the correction?