sage

Hello everyone. I have a 97 5 speed 4runner (4wd) with 75000 miles on it. A few questions before I take it to the dealer. I did a search but did not get my questions sufficiently answered. I'm less than a novice with maintenance but I'd like to make sure the right work is done. Hope someone can help:

1. What exactly is a PCV valve and when should it be replaced?
2. How do I know when my oxygen sensor needs to be replaced?
3. For a manual transmission is there transfer case fluid, if so when should it be replaced?
4. Last dumb question, if my brake fluid has been changed, I'm assuming this is the same fluid for the clutch, am I right?

Thanks in advance for your help.

Mr pogo

1. Stands for Positive Crankcase Ventilation, sucks blowby emission fumes out of engine crankcase to intake manifold to lower pollution. A malfunctioning PCV valve can cause poor mileage, idle and leaking engine seals/gaskets.
2. When the check engine light (aka MIL) comes on.
3. On MTs, usually same as trans fluid and changed at same time. Some ATs also use ATF in transfercase.
4. Generally clutch uses same flavor of brake fluid as brakes do.

All this info can be found in the owners manual service schedule. Also Chiltons service manuals have the factory service schedules included.