U660F Planetary 2006

This is a new underdrive planetary gear set for the Toyota and Lexus U660F all-wheel-drive six-speed, listed for units from 2006 onward and also built for the front-drive U660E. It is aimed at the rebuilder or owner who has opened a noisy unit and found worn pinions, a pitted ring gear or needles in the pan. The 2006 in the name is the first model year it is listed for, not the only one. The photo shows the carrier with pinions, a separate ring gear and its housing, the gear shaft, a snap ring, two needle thrust bearings and a flat thrust washer.

Why the U/D set matters in the U660F

The U660 family uses only two gearsets: a Ravigneaux unit and a simple underdrive planetary, which ATSG lists at 66 sun teeth, 21 pinion teeth and 110 ring teeth. The U/D set is where engine torque gets its first reduction before C1 passes it on, so it is working every time the transmission is in first through fourth. Early AWD units in Highlander and RX 350 service have the most miles and heat on them, and those are the ones most likely to show pinion wear today. When the pinion needles go, the gears lose their mesh pattern and start to sing.

Warning signs

• Whine that climbs with road speed and is worst pulling away or climbing hills
• A growl that quiets on the highway once the unit is in the upper gears
• Needles, flakes or a bronze tint in the old fluid and filter
• A thump or loss of forward drive in the lower gears if a pinion shaft has failed

Checking before you order

On AWD models, take the rear driveline out of the equation first; a failing rear differential or transfer bearing can sound like a gearset. Inspect the pan and filter, and confirm the fluid level was right, because a unit run low will also make noise. Hydraulic wear in the valve body is the most common U660 complaint and is covered, along with the shudder issues, in our U660E and U760E problems guide. A gearset is the answer when the debris is metallic and the noise is tied to the lower gears.

Fitment and matching your unit

Listed fitment: U660E and U660F transmissions in Toyota and Lexus vehicles from 2006 on. Vehicle compatibility can vary by production year and internal revision, so do not order on year alone. Compare your old carrier, ring gear and shaft with the photos, count the teeth and splines, and check the outside diameter of the ring. Send us your year and VIN if you want us to confirm. All parts for the family are on the U660E/U660F collection page.

Installation points

• Use the two new needle bearings and the washer in place of the old ones; reused thrust parts are a common cause of repeat noise.
• Set and record end play after the gear train is assembled.
• Look at the case where the gear train bearing support sits. Gears Magazine reports wear in this area on the U660E, and a moving race will wreck a new gearset.
• Debris usually reaches the pump, so inspect it or fit a U660E pump. A U660E master rebuild kit for 2006-2011 supplies the clutches and seals.
• If the C1/C2 drum shows bluing, the U660F clutch drum is the matching replacement.
• Refill with Toyota WS only and set the level hot per Toyota's procedure.

Need the kit with a different thrust package? See the U660F planetary kit.

Does 2006 mean it only fits 2006 vehicles?

No. It is listed for U660E and U660F units from 2006 onward. Match the tooth and spline counts on your old parts, or send us your year and VIN.

What comes in the set?

The photo shows the carrier with pinion gears, the ring gear and its housing, the gear shaft, a snap ring, two needle thrust bearings and a thrust washer.

Is this the same as the U660E planetary?

The set is listed for both the U660E and the U660F. The AWD version adds the rear drive through the transfer but shares the gear train inside the case.

What else should I replace with it?

Frictions, steels and seals from a master rebuild kit, plus the filter. Inspect the pump and C1/C2 drum for debris damage, and flush the cooler.

How much fluid does it take?

ATSG lists 6.57 liters for the U660E including the differential. Fill with Toyota WS, then set the final level at 185-194 F with the overflow method.

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