tune up intervals

[4X4maestro]

We have an '04 Liberty (3.7L V6), bought new and is garage kept. I was wondering about tune-ups, such as new plugs. The manual says every 30K, but is it really necessary to do that that often? My dealership keeps trying to get us to do the 30K mile upkeep (new coolant, transmission, transfer case, differential fluids and spark plugs) which is $750! Is any of this really necessary? I want to take care of our vehicle, but I also don't want to get ripped off. Also, for you DIY'ers out there, what do you do with the oil you drain out of the engine when you change the oil? Thinking of starting to do this myself, and was wondering about that? Thanks. JD.

[Evil Genius]

we flip all the fluids, shocks and plugs every 30Kish because our libby is a high mileage commuter. Costs us less then 200 total. Our local dump takes oil for free, but if you want to get crazy, store it up in a 30 or 55 gal drum and take it to an 'environmental company' in your area, you should be able to sell the full drum for about $15. A little bit crazy, but i know a bunch of small shops that do it.

Don't throw used oil in the trash, obviously.

[Grit dog]

Used oil. Most Autozones and similar stores will take it for free, I think 5 gal max per month.
Spark plugs. I don't know anything about the 3.7's, but my 01 Ram was reccomended the same interval and I blew it off thinking all the newer plugs last a long time. By 45k miles they were shot! Misfiring, idling rough. Replaced w/ Bosch Patinum +4's. Just sold it w/ 120k on the clock, almost 80k mi on those plugs and it ran very well and the plugs still looked good. I'd reccomend to replace them w/ some high quality plugs and forget about it until at least 100k.
If you're going to start to do your own services, it's fairly easy. Oil changes, self explanatory. Diffs, drain and refill. SOme have a plug on the bottom to remove, others, you have to take the cover off. Messy and smelly, but not difficult. Trans, fluid and filter. Drop the pan, replace filter, refill. Flushing the trans (just changing the ATF only gets about 1/2 of the old fluid, flushing will replace whats in the torque convertor as well) is more difficult, requires disconnecting the return cooler line and starting the vehicle, letting the old fluid pump out and replacing w/ new at the same time, metering what comes out. Better left to a shop unless you have a helper.
SPark pugs, easy replacement if you can get to them; I don't know how accessible the 3.7 is.
Coolant change, pretty easy too. Drain out of radiator, petcock on the bottom somewhere. Drain out of engine, plug near the bottom f the block somewhere. Refill w/ water, run til warm and drain. Repeat a couple times until all clear. When adding new coolant back in, take the system capacity (say 15 qts, for example) from the owners manual. Figure how much coolant you need to add, undiluted. (For 70/30 mix, use 10.5 qts of undiluted new coolant). Add all undiluted coolant first and then top off the remainder of the needed capacity w/ water (some water will remain in engine after draining the last time). When full, run up to temp, then re check (after cool down) and add additional straight water to get proper levels in burp tank.