AW4 Master Rebuild Kit, new and ready to install. Fits the AW4. Ships fast from the USA.
If your Jeep Cherokee XJ or Comanche with the Aisin AW4 automatic is slipping between gears, flaring on the 1-2 or 2-3, smelling burnt, or leaking from more than one seal, the fix that lasts is a full overhaul rather than a single part. This AW4 master rebuild kit is the core of that overhaul: new friction discs and steel plates for the clutch and brake packs plus the seals and gaskets that reseal the case, so a tired AW4 comes back out of the shop with every wear surface renewed at the same time.
The AW4 is a four-speed, electronically shifted rear-wheel-drive unit that Jeep paired mostly with the 4.0L six from 1987 through 2001. Its valve body applies a set of multi-disc clutches, multi-disc brakes and a second coast brake band, with three solenoids sequencing the 1-2, 2-3 and 3-4 shift valves and the torque converter lockup. Every one of those clutch and brake packs wears a little each time it applies. Once the friction material thins, pack clearance grows, applies get late and soft, and the slipping that follows burns the fluid and accelerates wear in the other packs. A master kit replaces the frictions and steels together and supplies the piston seals, sealing rings and gaskets that leak with age, so pressure stays where the valve body sends it.
Start with the fluid. Pull the dipstick and the pan: severely discolored fluid carrying friction material or metal is the factory manual's own sign that internal parts have worn. Rule out the electrical side next, because a failed solenoid or neutral safety switch can make a healthy AW4 shift oddly or stay in one gear. Check solenoid resistance and the wiring before committing to teardown. If the solenoids test good and the unit still slips under load, the packs are worn. Our guide to diagnosing an Aisin that slips under load walks through the order of checks.
This kit is listed for the AW4 without a year split. The AW4 was used in the 1987-2001 Jeep Cherokee XJ, the 1987-1992 Comanche, the XJ-based Wagoneer and early 1993 Grand Cherokee ZJ models with the 4.0L. Jeep's own overhaul manual gives different clutch clearance and stroke figures for four-cylinder and six-cylinder versions, and seals and pistons changed over the production run, so confirm your transmission tag and compare the kit's seals to your parts at teardown. If you are not sure, send us your year and VIN before ordering. Browse every AW4 part we carry in the Aisin transmission parts collection.
Most rebuilders replace the shift solenoids during an overhaul since the valve body is already off; the AW4 solenoid kit covers all three. Burnt fluid also leaves debris in the cooler, so flush the lines or fit a new AW4 transmission cooler before the rebuilt unit sees its first heat cycle. A shift kit is a common add-on to firm up shifts on a Jeep that tows or wheels.
| Fits | AW4 |
| Part type | Master Rebuild Kit |
| Condition | New |
| Brand | OEM |
| Ships | From the USA |
| Warranty | 1-year |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
The 1999 XJ with the 4.0L automatic uses the AW4, which this kit is listed for. Because seals changed during the 1987-2001 run, compare the kit parts to your old ones at teardown, or send us your VIN before ordering and we will check it.
Yes. A master kit carries both frictions and steels along with the seals and gaskets, so each clutch and brake pack is rebuilt with new plates instead of reusing worn steels.
Jeep's overhaul manual calls for Mopar Mercon automatic transmission fluid, with Dexron II allowed if Mercon is not available. Most modern Dexron/Mercon multi-vehicle ATFs that list those specs are used today.
Plan on the three shift solenoids, any bushings that measure past their limit, the torque converter (or a converter service), and a cooler flush or new cooler. Hard parts such as drums, the pump body and pistons get replaced only if they fail inspection.
Not always. A unit that stays in one gear is often in limp mode from a solenoid, wiring or sensor fault. Check the electrical side first; a rebuild kit is the answer when the clutch packs themselves are slipping or burnt.
