So i guess I understand that they just say "inspect" an item at a certain mileage, for example Diff Fluid, and replace if necessary, but how do you know if you need to replace it?
in the FSM under Inspection, they basically just tell you to check the level, and add or drain fluid to get to that level. They don't however mention anything about checking for the quality or color of the fluid, so how are you really supposed to know when you need to change it.
For example Front and Rear Diff Fluid, they say to inspect every 15k miles, and replace every 15k miles under heavy use, like if you tow... but under normal conditions should you just be safe and replace it every 15k? That seems like a waste of it isn't necessary. Do you wait until it turns a bad color?
Also, they mention nothing about break fluid anywhere, so how are we supposed to know when to flush the brake fluid? Also, since the timing chain is not mentioned anywhere, do I assume it will last me 300k?
Also, they say ATF should be changed at 120k under heavy use...is that really true? Seems like a high interval to me, even under normal use. And at that point do you drain and fill or flush.
I just wish Toyota would be a little more clear on their maintenance. Its not like I can trust a dealer to tell me the proper maintenance intervals. heck, the last dealer website I saw has "Inspect the distributor cap" in their 30k service interval for a 2013 4runner.... 4runners haven't had those in a while....
Maintenance intervals are only for people who care or are concerned about the performance longevity of their vehicle. That excludes about 90% of the population that assumes, and rightly so, that modern vehicles will go a long time without anything being done other than oil changes every now and then. The truth is modern vehicles WILL go a long time with no real maintenance. The engineers have solved a lot of problems that plagued vehicles up into the 1990's. Wear items like distributor caps (gone), carburetors (gone), spark plugs (new materials science lets them last 100K or more), transmissions (many are sealed now with 100K between service intervals) and many other items that plagued vehicles in the past are simply not an issue today. The addition of special additive packages to create synthetic oil and lubricants mean the change intervals have gone way up too.
If you drive in severe conditions like miles of dusty roads daily or pull a large trailer frequently, then of course you will need to service wear items sooner. How soon? That's the big question.
[MENTION=8206]harper7[/MENTION] changes his oil typically every 5K miles and I change mine every 10K. He lives in a hotter part of the country than I do and goes off road more often in dusty environments. I drive more miles than he does but most of those are road miles. So you see we have different applications of the same vehicle which warrant different basic service intervals.
As far as brake and power steering fluid? As long as the system has not been compromised by such action like a line being torn loose or a hose blown, you should be able to go for years and years with the original fluid. Remember that fluid does not circulate. It just changes pressure. For example in your brake circuit all the lines are filled and at a static pressure. When you hit the brakes the pressure goes up, actuates the pistons, clamps the pad against the rotor and then releases when you take your foot off the brake. No real brake fluid flow, just a change in pressure. As long as Toyota did a good job of keeping the lines clean during initial build there will be no debris or anything in the fluid to cause reason to change.
All grease points need to be greased every oil change whether it's 5K or 10K. If you determine your oil needs changed at 5K then you should grease it then too.
Transmission is sealed. No dipstick anymore. Again, if you drive normal and don't tow a lot of heavy trailers that should easily last 100K before the fluid needs changed.
Spark plugs and timing chain are another 100K change item too. Technology is wonderful with the plugs now.
This leaves differential fluid. If you go through deep water you should change it. Water is the worst contaminant you can introduce into the differentials because they are not sealed as they require a breather as do most gearboxes.Transmissions and differentials are two different animals so don't get them confused. Many on here have relocated their differential vent to a higher location so they can go through deep water and mud with no worries. Many on here change the diff fluid early at 15K. I check mine then, also at 30 and 45K and changed it at 60K on my SR5.
I probably left something out but hopefully you see there is not a "one size fits all" maintenance schedule for a vehicle such as the 4Runner because it can and will be used in a wide variety of applications. Now,, something like a Corolla or maybe even a RAV4 will almost always be used the same way by 99.9% of the drivers. 4Runners? Not so much. Here is a wonderful post by [MENTION=49863]WhiskeyCop[/MENTION] that will help
http://www.toyota-4runner.org/5th-gen-t4rs/110839-5th-gen-maintenance-documentation-reference.html and is comprehensive. There's lots of other things that need to be checked at 5K or 10K intervals (hoses, fittings, bolt torque) that I'm sure you have already read about. Hope this helps.
