ok first there are only 16 spark plugs, yes they should be changed every 30k they are just cheap copper pluses, and plus they go into aluminum. You dont have to put ngks in, just plain ole champion copper plus 2.50 a plug. Diff fluids you mean? Thats easy transfer case easy. Do it all yourself save some dough. Transfer case pull the drain plug let it drain, pull front and rear diff covers, drian reinstall and refill. Or use a vacuum sucker and suck out fluid through the fill hole then refill. Plugs are easy take one out. Gap the new one brush on some anti seize and reinstall. Using a combo of extensions will get you into tight spots. Plugs took me 2 hrs the first time and i ve been working on cars all my life ( im only 23 tho lol) you can do all this your self and spend may 200 in parts. If you need more ask me im here. i would change them at close to scheduled intervals. do you tow? or haul alot that would be the deciding factor. if not you can let it roll for a bit maybe 40k but i wouldnt let it go any further.
Last edited by 04Hemi1500; 01-14-2011 at 08:49 PM.