I personally could sell that for $400 to $500 if its gauranteed. It is worth the swap IF you are going to run bigger tires, engine or abuse the Jeep at all. If you're leaving it stock and going to be nice to the Jeep, I'd leave it alone and save yourself the labor and headaches.
The 176 and 177 are medium duty trannies, while the T4 and T5 are light duty. I'm running a T4 right now, with 33's, and it's holding up. But yeah, it would be a good swap. Like Racinrudy said, big tires, hard wheeling, the 176 will hold up better/longer than a T4.
I'd pay 4-5 bills for one with that few miles on it, as long as it's good. (hasn't been sitting out in a field for a year, stuff like that)
i just swapped to a T-176 from a T-5 and im liking it so far...it looks like replacing the bearing on the input shaft is a PIA (although a guy told me in an e-mail that it wasn't, who knows)...its harder to shift back and forth from 1st to reverse although it could just be cause i've only had it in for 3 months...it feels like the older style tranny that it is...much more like a truck, but very smooth shifting, clicks into each gear nicely...the T-5/4 is alot more like a dirtbike tranny in that you can pretty much just bang it into gear while the T-176 is a little pickier...with a T-176 you have to change the bellhousing and driveshafts though (longer rear and shorter front so theres a plus in driveline vibration offsetting the cost)...i just got lucky and found the whole package, bellhousing, tranny, t-case adapter, transfer case, plus front and rear driveshafts setup for a 4-inch lift and even the correct gear in the D300 for 35 inch tires...it was a great deal and a lucky find for my daily driver after it puked another input shaft and cluster from the T-5...good luck with the swap, just move your tranny mount up a slot on your cross member and the same with the crossmember to frame mounts...all the holes are there