U660E Input Drum

Most people searching for a U660E input drum have already had the transmission apart and found something they cannot reuse: a twisted or cracked input shaft, scored sealing ring lands, or a drum that let the forward clutch burn up. This is a genuine Toyota input drum assembly, part number 35650-33010, with the input shaft, both pistons and the original clutch pack, taken from a working U660E out of a V6 Camry, ES350, Avalon, Venza or Sienna. The shaft splines, gear teeth, drum and pistons are clean and structurally sound. The steels show heat discoloration, so plan on new frictions and steels when you build it.

Why the input drum matters in a U660E

The torque converter turbine drives the input shaft, and the input shaft is part of this drum, so every bit of engine torque enters the gear train here first. Toyota calls it the C1/C2 drum because it houses both driving clutches the U660E has, according to ATSG. Fluid for those clutches travels through the case and up the shaft past sealing rings to reach the pistons. When the shaft splines, the bushing journals or those ring lands wear, apply oil leaks off and the packs slip even with good line pressure. Gears Magazine adds a U660E-specific problem: the case wears where the main gear train bearing support mounts, the unit loses its centerline, internal bushings wear, and in extreme cases the converter input spline area breaks away and the vehicle will not move.

Symptoms of a failed input drum or shaft

• No movement in any gear after a bang or grinding noise, a sign of a broken input spline
• No Drive but Reverse works, since ATSG shows C1 applied in first through fourth and not in Reverse
• Flare on the 4-5 shift or slip in fifth and sixth from a leaking C2 circuit
• Bushing material, aluminum or burnt clutch lining in the pan
• Engine speed rising with no road speed as the fluid gets hot

Check these first

A no-move condition can also be the converter, the case bearing or a fluid problem, so confirm what broke before you buy. Check the WS fluid level hot and look at what is in the pan. With the unit out, spin the converter hub and turbine spline and inspect the input shaft splines. If the car still drives, gauge the C1 and C2 pressure taps that ATSG locates on the case: normal pressure with slip means the drum, low pressure everywhere points at the pump or valve body. Our U660E and U760E problems guide walks through those tests and the TCM faults that can mimic them.

Fitment

This assembly fits the U660E six-speed front-drive transaxle used behind the 3.5L V6, which Gears Magazine dates to the 2007 Camry and ES350, the 2008 Avalon and the 2009 Venza, plus the Sienna and front-drive Highlander and RX350. It also fits the AWD U660F. Toyota changed this drum during production; we stock an early 2007-up input drum and a late 2010-up version separately, so lay your old drum beside the photos and match the shaft length, spline count and sealing ring grooves. The four-cylinder U760E drum is different. Not sure? Send us your year, model and VIN. All parts for this family are on the U660E collection page.

Install notes

• Repair the case bearing bore before installing a new drum. Gears Magazine says that if the outer bearing race moves at all, the case must be repaired or replaced.
• Install new frictions, steels and shaft sealing rings; the U660E overhaul kit covers the seals and gaskets.
• Inspect the pump bushing and stator support. A worn U660E pump will chew up the new drum's journal and rings.
• Air-check both clutches, set clearance to spec, and replace the converter if the turbine spline is damaged.
• Fill with Toyota WS, set the hot level per our U660E fluid guide, and reset the transmission learned values.

Is an input drum the same as the C1/C2 clutch drum?

Yes. On the U660E the input shaft is part of the C1/C2 clutch drum assembly, Toyota 35650-33010, so the two names describe the same part.

My shaft splines broke and the car will not move. Is this the fix?

It replaces the drum and input shaft. Gears Magazine ties broken input splines to case bearing bore wear on the U660E, so inspect and repair the case and check the converter turbine spline at the same time.

Does it include clutches?

It includes the original clutches and steels, but the steels show heat discoloration. Install new frictions and steels and new sealing rings before final assembly.

Will it fit a U660F all-wheel-drive unit?

Yes, the same drum is used in the U660E and U660F. Match the shaft length, splines and ring grooves to your old part, since Toyota revised the drum during production.

What fluid does the U660E need?

Toyota WS only. Check and adjust the level hot through the overflow plug as described in Toyota bulletin T-SB-0036-13.

• Toyota/Aisin U660E and U760E: Shudder, Valve Body Wear, and the WS Fluid-Level Procedure
• U660E Fluid Type, Capacity and Service Interval