Transfer Case Seal
On a 2009 Escalade, 2008-09 Avalanche, Silverado,
Suburban, Tahoe, Sierra, or Yukon equipped with Magna
transfer case RPO NQF, NQH or NQG, a customer may
comment on transmission slipping or surging, transmission
fluid low or a leak out of the transmission vent. The transfer
case may be overfull.
These concerns may be caused by the transfer case input
seal allowing fluid to migrate out of the transmission into the
transfer case. If the vehicle has transmission concerns such as slipping or surging and
this is a repeat transmission concern, or there is a fluid leak from the shared vent,
inspect and if necessary replace the transfer case input shaft seal.
– Thanks to Chuck Krepp
7
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Typical transfer case input
shaft seal condition
Moan Noise
In rare occurrences, the owner of a 2007-09 Aveo, G3 or Wave (Canada) equipped
with a 5 speed manual transmission may comment of a resonation or moan noise
that is heard and or felt while driving at 55-60 mph (89-97 kph). The condition is most
noticeable on smooth, level roads with a light load. Engineering is currently working
to identify the root cause and develop a correction for this condition.
Repairs in the field have been unsuccessful in correcting this condition. Until a
root cause and viable correction have been identified, repairs should not be attempt-
ed. Advise the customer that this condition should be considered a normal vehicle
characteristic and can be compared to a like vehicle.
– Thanks to Jeff Gorenflo
TMAP Modification
When installing the Performance Parts accessory upgrade
Stage I Turbo kit on a 2008-09 HHR SS, the intake air pres-
sure temperature (TMAP) sensor interferes with the charge
air cooler (CAC) pipe .
The sensor requires modification before assembly, or leaks
may occur. Engineering is currently
reviewing this concern and a ser-
vice procedure has been developed
until the parts can be updated. Following these steps will
prevent any concerns when mounting the TMAP to the
CAC pipe.
The boss must be removed to prevent interference with
the alignment tab on the CAC pipe. Carefully clearance the
boss until the TMAP will mount flush.
– Thanks to Jeff Gorenflo
TMAP before modification
TMAP with boss removed
Slipping Clutch Conditions
In rare instances, some owners of a 2004–09 GM passenger car or light duty truck
equipped with gasoline engine and manual transmission may comment that the
Service Engine Soon (SES) light has illuminated. Upon closer inspection using a Tech 2,
DTC P0502 (vehicle speed sensor circuit low voltage) may be found stored in the PCM.
Follow the appropriate diagnostic information in SI. If no cause for the DTC can be
found, the condition may be customer induced. Supporting data may be found in the
freeze frame info stored with the DTC.
For help in diagnosing the vehicle, review Tech 2 data parameters: Calculated Engine
Load, Engine Speed, Output Shaft Speed Sensor and Clutch Pedal Position.
Inform the customer that excessive slipping of the clutch with the vehicle stationary
or moving at low speeds may cause this DTC to set. This is considered normal vehicle
operation. Engineering is currently investigating the concern and updated information
will be released when it is available.
– Thanks to Jeff Gorenflo
