I just got done replacing the alternator decoupler on our 2006 CRD. Many thanks to those who posted on the longer thread here. I would have wasted a ton of time and money chasing what I thought was a problem with the tensioner. I wanted to post my results of the repair here so folks don't have to dig through the other thread.

1. The part number has been superseded - it is now 53013554AF
2. I did have to remove the alternator from the engine, since there was not enough room for the tool, and especially not enough for working with an impact wrench.
3. Instead of the Miller tool, I used Lisle tool 57650 - Alternator Decoupler Tool Kit. It contains the tools for both the splined and hex decouplers, and costs $34 from O'Reilly rather than nearly $95 with shipping from Miller for just the hex tool. I have photos of the kit (doesn't look like I'm allowed to post them here).
4. The tips people had of using an impact wrench for removal were spot on. I tried using the tool as designed with two wrenches, no effect. I then used an impact wrench on the center bolt, going clockwise as directed, while holding the hex portion with a wrench, no effect. Then, even though I figured it shouldn't work because of nearly no resistance, I tried the impact wrench on the hex, going counterclockwise, by itself. Spun the decoupler right off.

Decoupler was frozen, and the face cracked. Belt squeal is gone, engine quiet again.
Lastly, again, thanks to those who paved the way before me and documented their experiences. I would have been lost without it.

Dave

ID Parts also sells the Lisle tool kit for $29.95

http://www.idparts.com/catalog/product_info.php?cPath=30&products_id=3737

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2006 Liberty CRD Limited

Provent @ 43,000 km
SEGR in progress
SAMCO Sport hoses @ 48500 km
Goodyear Wrangler Duratrac LT225/75R16

Dave, what decoupler did you use, OEM or aftermarket?

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.

OEM, ordered from moparpartsamerica.com

Dave

Cool, thanks a lot!

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2005 kj CRD, samco, suncoast tc, provent, Kennedy lift pump, GDE ECO full torque, 2nd gen filter head, 245/70/16 a/t tires, mopar light bar, fumoto oil valve, OEM Skid Plates, ARB Front bumper and HD OME, tru cool LPD47391 40k GVW tranny cooler (stock cooler delete), FF Dynamics e-fan and shroud, rocker arms replaced, HDS2 190F thermostat.