no
It isn't feasible to convert from two wheel drive to four wheel drive.
The 1990 Cadillac Sedan DeVille is front wheel drive. The 1990 Cadillac Sedan DeVille is front wheel drive. The 1990 Cadillac Sedan DeVille is front wheel drive.
The 2005 Cadillac SRX has rear wheel drive.
The 2009 Cadillac SRX has rear wheel drive.
The 2013 Cadillac SRX has front wheel drive.
The 2011 Cadillac CTS has rear wheel drive.
The 2006 Cadillac CTS has rear wheel drive.
The 2004 Cadillac CTS has rear wheel drive.
The 2013 Cadillac XTS has front wheel drive.
The 2011 Cadillac SRX has front wheel drive.
The 2014 Cadillac XTS has front wheel drive.
The 2013 Cadillac ATS has rear wheel drive.