My rear end suppension which levels per weight disrubution is not staying up. Have to have envoy running for awhile before it kicks in. What needs to be replaced or how can I fix it. Is it a costly fix as well?

There is a level sensor connected to the lower control arm on the rear wheel on the drivers side. This operates the pump and lets air out if it is too high in the back.It can fail. Most likely the air pump has gone bad. Expect 800 + to fix it.

There has been a service bulletin for that type of concern. Here is what it states.









Suspension - Rear Suspension Is Low/Sagging/Uneven

Notes




ENGINEERING INFORMATION

Bulletin No.: 06-03-09-006B

Date: December 15, 2008
Subject:
EI06006 - Rear Suspension Uneven, Sagging, Low (Recalibrate Air Spring Sensor)

Models:
2006-2007 Buick Rainier
2006-2007 Chevrolet TrailBlazer SS
2006-2007 GMC Envoy, Envoy XL
2006-2007 Saab 9-7X


with Suspension Pkg - Rear Load Leveling (RPO G67)

Supercede:

This bulletin is being revised to update the labor operation in the warranty information. Please discard Corporate Bulletin Number 06-03-09-006A (Section 03 - Suspension).

Condition

Some customers may comment on the rear suspension being uneven or sagging.

Correction

DO NOT REPLACE THE COMPRESSOR.

Based on technician feedback, engineering has determined that the customer's concern can be corrected by recalibrating the air spring sensor. Refer to the Trim Height Uneven or Low diagnostics and Air Spring Sensor Calibration procedure found in SI.

The air suspension system should stay up for several days without going completely down, which probably means that you have a small leak which is quite common even on relatively new air bags or struts.

A general rule of thumb is that if the compressor isn't kicking on several times during a drive then they are good to go. The air bags are a pain to change, so most people don't change them until they are really bad.

Mine does the same. Couldn't find a fix.I am not sure if this is weather dependent. It does more when it is cold. i am afraid that one day it will stay low where the hydrolic give up Please share your solution if any

Most vibrations are driveshaft being bent,worn u-joint,in need of balance,shocks,wheels,tires and more.I will bet ,swapping the complete rear axle will not change a thing. If it is lifted, you should know your in for problems. If not, and all else fails,strip the rear housing and go through it. The one you swap, may be more worn than yours and not even a good core to rebuild.

chek the transmission fluid level in park engine running . it should be in marked area. also if it is dark brown instead of bright red get the fluid flushed and change filter.if all o.k. but still slow shift you may need a pump.

the air suppension has a lever on the rear axel
will want to check the lever and the sensor and make sure it hasnt come loose or bent and yes its adjustable. if it doesnt adjust you might have a bad sensor or air leak

sound like poss. speed sensor problem.

Can you hear the pump kick in when you put weight in the back and the car is running? The way it works is there is a level sensor that mounts between the body of the car and the rear axle. When weight is added in the rear the compressor will add air until the vehicle is level. When weight is taken out of the car which could be the rear passengers getting out of the car the vehicle is now higher and the pump will release air to lower the shocks back to a level height. This is why youare hearing that sound. The pump will let air out of the system even when the engine is off to maintain a level ride. If you found this solution helpful please rate it.

Thanks - Tech101