whats up guys, so i have a few questions.....i just picked up a 2007(newer body style)crew cab Z71 silverado and it has 127,xxx miles on it, this past weekend i did the oil change/spark plugs and wires and next weekend i want to change the transmission fluid,transmission filter, and front and rear differential fluids, so my question is what grade of oils should i get? such as fully synthetic for that high of mileage and what grade? any info would be greatly appreciated.thanks oh and what transmission is it that it has? 4l70? thanks