Two problems related to rear suspension have been reported for the 1999 Toyota 4Runner. The most recently reported issues are listed below.
Several suspension and structural components of my 1999 4runner are showing excessive rust. The worst of which is on the rear axle and differential housing. I've recently had to weld a broken stabilizer bracket. The differential housing has rusted so bad that a hole has formed and gear oil is leaking.
Purchased new - now at 135k miles. Have replaced 1 or both rear axle seals at least 5 times -- first replacement was on my dime -- remainder have been under warranty. They replaced an axle last time, but in less than 2k miles symptoms returned (leaks on wheels, sticking rear brakes). Sure, it doesn't "cost" me anything, except my truck is in the shop 1-2 days each time!.