I agree with Dave that this looks like an ex-Aleyska Tucker.
They bought a bunch of Tuckers and as he said kept them incredibly well maintained. Back in 2011 (I think) they auctioned off a bunch, maybe eight or so, in Fairbanks, AK. They were all 1743s and 1744s with Detroit 4-53T engines, Allison AT-545 transmissions and Warn winches. I thought about going to the auction, but:
A.) I already had three Tuckers.
B.) I thought the auction would draw a lot of buyers and there would be no bargains.
C.) Getting it shipped would be cost prohibitive.
Of course they all went cheap!
http://www.forumsforums.com/3_9/showthread.php?t=48245&highlight=fairbanks+auction
Some may remember forum member Firedozer who had a beautiful 1744. That was sold at the auction to a mining company who decided not to use it and he got a smokin' deal on it.
http://www.forumsforums.com/3_9/showthread.php?t=75312&highlight=1744
The 1700 series machines are significantly heavier than the 1600 series. The data plate shows an unloaded weight of 7,710 lbs. If anyone is seriously interested in this machine you might think about calling Tucker and asking them to send you the order sheet for this Tucker. You'll need to give them the serial number for them to look it up. That will give you all the specs on the order.
A little over two years ago another 1743 came up for auction in North Dakota. This one looks to be virtually identical, though in slightly better shape. It went stupid cheap at $7,750.
And is was discussed in the forum:
http://www.forumsforums.com/3_9/showthread.php?t=72838&highlight=ritchie+brothers+1743
OOPS, I see Glacier Sean posted that link while I was composing my reply...