G8 V6-3.6L (2008)
26. Install the engine mount-to-subframe nuts (both sides).
27. Install the engine starter and attaching bolts.
28. Connect the electrical leads to the starter.
29. Install the heat shield nuts to the engine starter.
30. Install the right side forward catalytic convertor to the vehicle.
31. Install the right side forward catalytic convertor-to-intermediate pipe nuts.
32. Connect the right side O2 sensor electrical connector.
33. Remove the screw jack under the engine and lower the vehicle.
34. Install the right side exhaust manifold-to-forward catalytic convertor bolts (from above with a long extension).
35. Install the engine acoustic cover.
36. Connect the battery and close trunk.
37. Remove the fender covers and close the hood.
Propeller Shaft Imbalance
Propeller shaft imbalance can be identified by the use of the EVA diagnostic tool. This type of vibration may be felt and/or heard. Compared with tire
vibrations, this type of vibration is much higher in frequency and can often be felt more than seen in the steering wheel. However, steering wheel
oscillation is still possible. The creation of boom or moan is not typically present with the other possible vibration sources.
If you can start to hear the vibration as a low boom noise (in addition to feeling it), but cannot see it, it likely has a first order (one pulse per propshaft
revolution) driveline vibration. Driveline first order vibrations are high enough in frequency that most humans can start to hear them at highway speeds,
but are too high to be able to be easily seen. These issues can be caused by driveline imbalance or misalignment. If the vehicle exhibits a low boom and
the booming pulses in-and-out on a regular basis (like a throbbing), these are indications of driveline vibration.
EVA Transducer Locations
It may be preferred to start with the EVA magnetic transducer attached to the driver seat frame or the steering column tilt/telescope lever. At these
locations, any tire vibrations should be sensed, as well as propshaft vibration, to help identify the proper source. If propshaft vibration is detected, it will
center around the 46 HZ frequency range. This frequency may change with road speed from the 45-55 HZ range. However, there is a tendency in this
vehicle structure to resonate centered at 46 HZ with amplitude increasing or decreasing as you drive into the target speed range of 55-70 mph (88-112
km/h). If propshaft vibration is detected, or any boom noise is part of the customer concern, move the sensor location to the trunk floorpan above the rear
of the propshaft for secondary testing.
Tip
You can utilize the rear seat trunk pass-through to easily locate the transducer to the trunk floor.
There is often some very small amount of vibration associated with nearly any spinning mass. Typically, EVA readings of 0.07g or lower indicate a
value that is acceptable to the customer and do not necessarily identify a concern with this component.
If a higher value is detected and determined to be first order propshaft vibration, replace the propshaft. Please refer to the instructions under the Parts
Information section below for propshaft exchange guidelines. Please refer to SI for Propshaft Replacement instructions.
Warning
When replacing the propshaft, DO NOT remove or torque the propshaft to rubber coupler bolts. Exchanged propshafts will come with the rubber
couplers installed and torqued to specification.
Note
Replacement propshafts are only available on an exchange basis directly through GM Brand Quality (except for 2008 MY V6 equipped vehicles). If it is
determined that a propshaft replacement is required, you will be expected to furnish written data to GM Brand Quality validating diagnostics of the other
possible components.
Parts Information
Propshaft Exchange
To qualify for a propshaft exchange, you must furnish your tire radial force variation numbers, along with the EVA numbers, collected during
road testing as well as any vibration repair history on the vehicle. GM Brand Quality will request this information and make a determination
on whether an exchange propshaft is required.
