This could be a number of things. I would say it deals with the transmission and not the differential because of the way you described its shifting pattern. Has the check engine light come on? If it has, have you had the computer scanned for trouble codes?
This problem could deal with many things such as shift solenoids, vehicle speed sensors, computer. Without a trouble code, it becomes a guessing game.
Let me know.
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Sunday, August 11th, 2013 AT 9:10 PM