Ok so kinda exaggerated about the blowing up part. Though when I think of people doing it on the road I can picture a person driving on the highway when a little rain starts to fall. Thinking it would be a great idea to turn on 4wd to keep from spinning.
Kevbz - For the most part it is the same. Though the d44's should come with a LSD and he will have a bunch of friction clutches in there as well. You can tell by the shape of the carrier. If it necks down from the R&P it is open, if its the same width all the way across then it is an LSD carrier. Here is a pic of my old one that is an LSD. Also if the R&P are messed up then now is a good time to regear to a new ratio. But since you could drive on it(and didn't complain with noise driving straight) and it was locking your wheels together only while turning all my money is on the spider gears.
Also since I just love exploded drawings, here is a d44's parts. Follow the link to get the part names and numbers. If all you need are the spider gears and clutch plates it's ~300 in parts and a competent shop could do it in 2 hours or less. Hopefully only a $500 fix. Or do it yourself and save and learn.
Dana 44 Rear Axle for Jeep Wrangler TJ at Morris 4x4 Center