Hi all,
As the title might suggest, I’m getting ready to do a bit of maintenance on my beloved 2004 V8 4wd 4Runner at 265,000 miles and looking for suggestions as to what to take care of vs what to leave alone. Overall it runs fine, I stay up on regular maintenance but I’m planning on doing some more major items soon, including:
Timing belt/water pump
Replace ALL fluids (transmission, front/rear diffs, transfer case, radiator, power steering, brakes)
Grease driveshaft (remove and grease, not just grease zerk it)
Serpentine belt
Valve cover gaskets (have a slight seepage on driver side bank)
Spark plugs
PCV valve

Since I’m doing the Tbelt and water pump, should I go ahead and do cam seals while I’m in there or anything else? I don’t have any visible leaks aside from the valve cover, but figure while I’m in there I should since to my knowledge the previous owner didn’t do them at its first TB change; however some say if they aren’t leaking don’t change them. Figure maybe I should change the tensioner and idler pulley while I’m at it too, but don’t currently have problems there that I’m aware of. Otherwise, it’s pretty mechanically sound so despite the fact that other things COULD be replaced, I don’t really see the NEED to do so yet. Thanks for any suggestions/tips that might come!

I would not do the camshaft seals unless they're leaking because they're hard to get just right so they don't leak, I would however do the idler and tensioner because of you don't and they go bad you will have to do the whole job again.

If you're running your original alternator, replace the brushes in it.
You basically have to remove it to do the timing belt anyway, and the alternator by itself is a pain so do it now while you have it apart.

27370-20130 is the part number, only takes like 5 minutes to pull the old ones out and put new in.

I didn’t see any chassis or body related items in your list. How are the:

Stabilizer bar links
Stabilizer bar bushings
Steering tie rods
Radiator (any leaks?)
Battery hold down (mine was nearly rusted out at 200k miles)
Moonroof lubrication

PCV replacement takes 5 minutes, here's my write up:

V8 4Runner PCV valve replacement with pics

The spark plugs are pretty easy too, as long as they aren't stuck. The passenger side plug closest to the firewall is tough to access, so make sure your socket set has a good extension and possibly a flex connection. It was a weird angle accessing that plug. All seven other plugs were pretty easy. I belkieve I used NGK Iridium plugs. Those or Denso are OEM, if I recall.

As for the fluids - I've done all of them personally except for the radiator. I used Mobil 1 Full Synthetic (75w90 i believe) for the gears and transfer cases. Make sure you have a fluid pump.

That's a good idea! I wouldn't have thought of that, thank you!

Good eye! I actually left chassis off because I've done the CV joints, sway bar end links and bushings in the last year or so (well, except on the rear--so I guess I could get those done), as well as new brakes (rotors,calipers, pads) in the last six months. I don't think I'm losing any fluid from the radiator, battery hold down is good, just replaced battery a few months ago as well. Didn't think of the sunroof, rather not even have the damn thing!
I would like to go nuts and do wheel hub assemblies, upper and lower ball joints, all the way around but will probably save that for until I've got one going bad.
I think I will replace some U joints though, have a clunk when shifting from reverse to drive that I imagine is one of them going bad. I just greased them all a few weeks ago and they all took, however I didn't check for play.

I actually just did the PCV valve last night! Haha!

If your going to do the valve cover gaskets. You should replace the Spark Plug Tube Seal Gaskets, since you have the valve covers off.