I have this same truck except in for mine being the 2002 model year.
I have not had any of those problems except for the oil leak which turned out to be one of the Turbo oil tubes leaking. The cost to repair was under $200.
I will say though that you need to watch out for the front rotors blistering, the wheel bearings on the front axle, the Cam sensor on the front of the motor, and the front ball joints. All of these items, I have replaced.
I have heard that others have had problems with the transmission, but I am at 102K and have not had issues yet, but I'm sure I will.