lost my manual how much oil do you use in a 2001 5.3l, also trans. fluid. does anyone beleive that synthetic oils/fluids are worth the money. and do they work that much better.

 

I don't have a listing for your fluid capacities but I can say that I believe synthetic lubricants are the way to go. They work real well in extreme cold and hot temps. When cold they flow like water and when extremely hot they do not carbonize like convential lubes. I my 92 Chev 4X4 I gained 1 mpg after changing my differentials, transfer case and engine to Mobil synthetics. The MPG gain came from a reduction of friction and anytime you reduce friction, that is a good thing. FYI, my 2005 5.3L engine takes 6 quarts when I change the oil.