Okay despite this horror story I have done the plugs for the second time at 62k I did it the first time at 30k. It was not that bad just a pain since halfway done you think damn on a 318 I would be done
I had a Durango before this so got pretty good at the dreaded hemi 16 plug swap. I also did the transfer case which is very easy. ATF+4 of you have no auto 4WD on the dial. Special dealer only NV246 fluid if you have the auto 4wd. You will need 2 quarts of the correct fluid and the job is easier than changing oil so cost is only the fluid. The diffs are easy I have done both of mine twice as I two a lot and again if you are even slightly mechanical just do it and only cost is about 5 qts of 75w-90 or 75w-140, ATV gasket maker, and your time for both axles. I have done the transmission fluid drain twice so far as well but will do it again so with both filters at 70K or when I feel like it. I can do it myself and save or just pay a small shop since it is so messy. Cost 60 bucks here. Fluids will kill things if not repaired the spark plugs can probably make it longer with neglect and only adverse effect I can think of is poor running truck won't actually hurt it.