Two problems related to differential unit have been reported for the 2008 Toyota 4Runner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Toyota 4Runner based on all problems reported for the 2008 4Runner.
Frame rust is so pervasive on my 2008 4runner that the Toyota dealer refuses to make necessary repairs to transmission. The dealer suggested that I "walk away from the vehicle", citing future rust-related problems with caliper replacement and other routine maintenance. Rust on differential axle led to the shearing off of the fluid drain bolt, rendering that impossible to drain/refill. Attached are notes from the dealer's maintenance engineer, citing rusted cross member bolts and other components interfering with necessary repairs. I have serious concerns about the ongoing safety and road-worthiness of this vehicle.
There is corrosion in the frame and drive-train components. There is pitting, rusting throughout the frame undercarriage and the suspension and differential components. This barely 4yr old vehicle is a southern vehicle. Regardless, this corrosion is a safety issue in any vehicle let alone in a 4runner with a service inception date of 11/30/2008 with 19k miles. This is totally irresponsible of the manufacturer and they claim it is not covered by warranty. Yes, it (should be) covered by warranty and more importantly it is manufacturer's liability to correct safety/quality issue.