My ever-dependable Murano started acting up 250 miles from home in Reno NV yesterday. Drove up to Mt Rose summit (8000 ft) & noticed it seemed sluggish with one instance of slight hesitation. Then it would lose power after a stop. Dealer here diagnosed it & the transmission needs replacing. To the tune of $4000. It currently has 120,331 miles on it. Any chance this would be covered under the extended warranty or do they cut it off right at 120K?