At higher mileages (125,000 -150,000) the power steering pump may begin to leak on the 6 cylinder vehicles and could require replacement.
Car Problem Reports
Toyota 4Runner Power Steering Pump May Leak on Higher Mileage Vehicles
Toyota 4Runner Problem
Average Mileage: 235,548 mi (116,000 mi - 322,000 mi)
Visitor, 1990 Toyota 4Runner, 322,000 mi
power steering leaking around the driver side close to the front
Visitor, 1994 Toyota 4Runner, 116,000 mi
replaced power steering pump
Same over here, started leaking at about 220,000. Even leaks with the heavy leak-stopper style fluid.
Visitor, 1991 Toyota 4Runner, 278,792 mi
Power steering fluid leak. I have to put in a bottle a week. Working on finding an inexpensive fix.