I wouldnt take the chance, but thats just me. I bought my truck a year and a half ago with 116k on it..the extended warranty was good till 144k or feb 2014.
The previous owner had the egr cleaned, arp studs, headgaskets, and new oil cooler all done under warranty. Then I got the truck, had $1800 worth of front end work done (hubs, axle shafts, etc) and then just a few weeks ago, had 2 gaskets replaced somewhere on the bottom end. That was worth another 2 grand. The gaskets are like $15 a piece, the money is in the labor.
I have gotten ALOT of money out of the warranty, so to me, it's worth it. Some ppl have great luck and dont get their money worth, but even if you have a good truck, those silicon seals will start goin pretty soon, and start leakin some oil. The labor to fix them is very high because often times the trans has to be dropped and engine raised.
Just my 2 cents.