AS68RC Clutch Drum 2007

This listing is a used K1 clutch drum with its input shaft, for 2007 and later Aisin six-speeds: the AS68RC, also sold as the A465 in Isuzu trucks and the AS6 in Mitsubishi Fuso. It comes loaded with a six-friction K1 pack and is 11-5/8 inches tall overall. It is the fastest way to get a cab-over or chassis-cab truck that has lost its lower gears back in service without buying a new drum and a separate clutch pack.

Why the K1 pack and drum matter

This drum is the input member of the transmission. Turbine torque enters through the shaft, and the K1 clutch inside the drum connects it to the gear train in 1st, 2nd, 3rd and 4th. A truck running a delivery route spends most of its day in those four gears, so K1 wears faster than the upper-gear clutches. Oil to apply K1 feeds through rings on the shaft. If the shaft lands are scored, or the pump stator shaft has turned and misaligned the feed holes, K1 loses pressure and slips. Transmission Digest explains that the same leak also bleeds into K2 and the converter clutch.

Signs your K1 drum assembly is done

• Truck pulls only in 5th and reverse, or will not move forward from a stop
• Slipping launch with engine flare, especially hot and loaded
• P0731, P0732 or P0733 ratio codes
• Burned K1 friction material and steel debris in the pan
• Snap ring out of its groove or a cracked drum at teardown

Diagnosis first

Note which gears drive and which do not. If only 1st through 4th are gone, check K1. If 4th through 6th are gone, look at K2 instead. Sonnax notes K2 burns are common on this unit. Use our P0730 ratio code guide to sort the codes, and the Aisin overheating guide to find out why the pack got hot. FCA's bulletin on the later AS69RC and AS66RC also describes a loose K1 snap ring causing exactly this no-1st-through-4th condition.

Fitment

The source item is tagged as Isuzu and Mitsubishi, 2007 and later, with a six-friction K1 pack and an 11-5/8 inch overall height. This one is used. If you want a remanufactured drum without the clutch pack, see the remanufactured K1 input drum. Ram AS68RC trucks (2007.5 and later cab and chassis) use a closely related unit, but Transmission Digest notes it is not identical. Compare height, spline count and ring grooves to your old part, or send the year and VIN before ordering. A complete clutch and seal set is in the AS68RC master rebuild kit.

Install notes

• Inspect the loaded pack and measure clearance. If the frictions are glazed or the steels are blued, rebuild it with parts from the AS68RC overhaul kit.
• Install new shaft sealing rings and air-check K1 before closing the case.
• Confirm the K1 snap ring is fully seated in its groove.
• Check the stator shaft splines in the pump, flush the cooler and refill with the fluid your truck's manual specifies.

Is this the same part as the remanufactured AS68RC input drum?

It is the same K1 drum and input shaft design at the same 11-5/8 inch height. This one is used and comes loaded with a six-friction pack. The other is a remanufactured bare drum.

Will it fit my Isuzu NPR?

It is tagged for 2007 and later Isuzu and Mitsubishi versions of this six-speed (A465 / AS6). Confirm height and splines against your old drum, or send the VIN.

Can I use it in a Ram 4500 or 5500?

Ram uses the AS68RC from 2007.5, and the Isuzu and Mitsubishi versions differ slightly. Match the shaft length, splines and ring grooves to your original before installing.

What causes repeat K1 failures?

The usual causes are a stator shaft that has turned in the pump and misaligned the feed holes, worn shaft sealing rings, overheated fluid, or a K1 snap ring that was not fully seated.

Which fluid should I use?

Use the fluid your truck's manual specifies. Ram AS68RC units take ATF ASRC or an approved equivalent such as Mobil 3309.

• Gear Ratio Codes P0730 Diagnosis
• Aisin Overheating Prevention
• Aisin AS69RC Problems and Service Guide
• Aisin Transmission Slipping Under Load