Three problems related to power train driveline have been reported for the 1997 Toyota 4Runner. The most recently reported issues are listed below.
Rust through on rear axle differential cover to the point of leaking approx 6 oz per week of gear oil. This cover is welded on to the rear axle and there is no possibility of replacing seperately.
1997 Toyota 4runner rear differential rust through. I have just noticed that my 1997 4runner is leaking differential oil and am concerned that rust or foreign debris will get into the differential and cause a catastrophic failure. I have removed the 4runner from operation until the defect is corrected. The rust is on the rear top of the differential. There are very large flakes of rust on the differential and the oil is leaking through some of the rust holes. It appears that the differential was not manufactured with adequate thickness in the metal housing and had inadequate corrosion protection.
No crash or injury,but 1997 Toyota 4runner differential is completely rusted through and leaks oil through numerous pinholes. It can't be patched and replacement is in the $1500 range. I can't take the vehicle on trips. I have found many instances of people complaining about this on the web - it seems to be a common problem.