See also:

Kia Sportage owners manual
...

Rear differential (4WD)
Checking or changing rear differential fluid Have rear differential fluid checked or changed by an Authorized Kia Dealer according to the Maintenance Schedule at the beginning of this section. ...

Introduction
The name Sportage doesn't really conjure up warm memories. Many folks remember the Sportage of yesterday, a crude cute-ute that was plagued with quality issues, a weak engine and a cheap interior. ...