Whatever alternator you decide to go with if you are lucky enough to find one with a higher capacity that will even fit the 2.8 CRD engine mounting brackets.
Be sure it has an "override" (one way) clutch pulley. If you don't, no matter what belt tensioner pulley/assembly you install, a non-override alternator pulley will self destruct the tensioner pulley/spring in short order.
As to the winch: Some, including myself, simply went to a much higher capacity battery like the NorthStar AGM Group 65 and still run the stock alternator.
A Group 65 AGM battery will fit in place of the OEM size battery with a slight battery tray modification.
The NorthStar AGM 65 with it's high reserve capacity would have no trouble running a winch. I have a single NorthStar AGM in my Dodge 4x4 gaser and it runs a 10k winch flawlessly.
NorthStar----------------------NSB-AGM 65
Pulse cranking amps-----------------1750 A
CCA rating at -18°C (0°F)-----------930 A
CA/MCA rating at 0°C (32°F)-------1070 A
Reserve capacity---------------------135 min
Capacity-20 hour rate (1.75 vpc)---69 Ah
As to the tensioner pulley:
There are plenty of cheap chinanism knock offs available, like the Crown brand tensioners listed online at eBay, Amazon, and many other places.
I would not waste my time or money on them and chance one of them coming apart and destroying the front of my engine or worse yet, causing catastrophic damage due to the serpentine belt flying off at some high rate of RPM's...
You get what you pay for!
SasquatchParts.com has a Litens assembly that is supposed to be of better quality than anything else available and is made in Germany.
LINK:> OE Litens Serpentine Belt Tensioner for Jeep Liberty 2.8L CRD
IDParts.com also has the OEM tensioner pulley assembly
LINK:> Serpentine Belt Tensioner OEM (Liberty CRD)
