About 275,000 of them, all told. 2005-2007 Cadillac CTS, STS, and SRX, 2005-07 Pontiac Solstice and 2006-07 Saturn Sky vehicles are included.

The problem is the rear axle pinion seal, which is potentially defective and can leak.  If it does, the fluid can leak out of the differential and the drive wheel can then lock due to the fluid loss. 

If this happens while the car is in motion, the driver could lose control. 

One such crash has been reported, and involved a collision with another vehicle.  GM has acknowledged that these vehicles have been the subject of an abnormally high number of warranty claims due to the problem, as well.
   
Recall notices will go out this coming February.  Owners may contact Cadillac at (800) 982-2339, Pontiac at (800) 620-7668 and Saturn at (800) 972-8876.