Power Steering Fluid Service
Mopar PS fluid (MS-5931) or generic ATF in early years. Suction reservoir, refill, cycle lock-to-lock to flush. No filter to change.
Pre-1998 XJs used Dexron-compatible ATF in the Saginaw steering box. From 1998 onward, Mopar specified its own MS-5931 power steering fluid (currently sold as Mopar Power Steering Fluid +4). Either fluid works in either generation in a pinch, but mixing the two can foam. There is no drain plug - the standard service is to siphon the reservoir dry, refill, cycle the steering lock to lock with the engine off, then start and cycle slowly until the fluid level stops dropping. A full flush requires pulling the return line and pumping fluid through while turning. The steering box itself can be a leak point at the pitman shaft seal - if you see fluid weeping there, a fluid change won't help; the box needs rebuild or replacement (ZJ box swap is a popular upgrade, see steering section).
Why it works
- Quiets pump whine
- Extends pump life
Trade-offs
- Full flush requires line disconnect
Tools required
- turkey baster or fluid pump
- rags
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Mopar PS fluid +4 | Mopar | ~$12 |
Sources
Related
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.