AW4 Input Drum, used and ready to install. Fits the AW4. Ships fast from the USA.
This is a used overdrive input shaft and overdrive clutch drum assembly pulled from an AW4 automatic in a 1998-2001 Jeep Cherokee XJ. It is the first hard part behind the torque converter: the splined shaft the converter turbine drives, the overdrive planetary carrier it is built into, and the drum that wraps the overdrive direct clutch. The photos show the shaft and drum assembled, alongside the overdrive ring gear. If your XJ slips or flares in every gear, has a high stall in reverse, or you opened the case and found a scored drum, a chewed shaft spline or a freewheeling overdrive one-way clutch, this is the assembly you are shopping for.
The AW4 is really two gearboxes in one case: a small overdrive unit up front and a three-speed Simpson gearset behind it. The factory overhaul manual describes the overdrive input shaft and planetary carrier rotating as one unit, with the overdrive sun gear and the direct clutch drum turning together. In first, second, third and reverse the overdrive direct clutch locks the sun gear to the carrier, so the front unit turns 1:1 and passes engine torque straight back to the rest of the transmission. The overdrive one-way clutch does the same job while the engine is driving the vehicle. In fourth, solenoid number two shifts the overdrive elements: the direct clutch releases and the overdrive brake holds the sun gear to make the overdrive ratio. That means a tired drum, a leaking piston or a worn one-way clutch in this assembly can make the whole truck feel weak, not just fourth gear.
Rule out low fluid and low line pressure first, since both mimic a worn clutch. The factory stall test is the quickest check: the overhaul manual lists the overdrive one-way clutch as a cause of high stall in D, in R, or in both, and lists a worn overdrive clutch as a cause of long engagement times in the time lag test. Our Aisin slipping under load guide explains how to read those results, and the transmission slipping diagnosis guide covers road-test patterns that separate the front unit from the rear clutches. On the bench, hold the drum and turn the shaft: it should spin freely one way and lock the other.
The listing is for the 1998-2001 Cherokee XJ with the AW4. The overdrive section stayed similar through the 1987-2001 run, but shaft length, spline count and drum details should still be compared side by side with your old part before you install it. Measure the shaft, count the splines and compare the drum to the photos, or send us your year and VIN and we will check it for you. Everything else we carry for Aisin-built units is on our Aisin parts page.
| Fits | AW4 |
| Part type | Input Drum |
| Condition | Used |
| 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.
Yes. On the AW4 the overdrive input shaft is built into the overdrive planetary carrier, and this listing includes that shaft with the overdrive clutch drum assembled on it, as shown in the photos.
It came from a 1998-2001 XJ. The overdrive section is similar across the AW4 run, but compare shaft length, spline count and the drum to your old part, or send us your year and VIN before you order.
In first through third and reverse, the overdrive direct clutch and one-way clutch lock the front planetary so engine torque passes straight through. If they slip, every gear except fourth slips with them.
New overdrive clutch discs and plates, piston O-rings, and the thrust bearings if they are worn. Most people install it as part of a full overhaul kit.
The factory manuals call for Mercon fluid, with Dexron II as the alternate. Check the level hot and do not overfill.
