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Most of these units that land on a bench are not worn out. They are units where a lockup clutch started chattering at 90,000 miles, the owner was told the transmission was failing, and nobody ever dropped the pan to look. Aisin built this transaxle strong — the clutch packs, drums and planetaries in a Camry or Sienna regularly see 200,000 miles. What quits is the torque converter lockup lining and the hydraulics that control it, and both run on a maintenance clock the owner's manual never mentioned.
Production started in 2007 behind the 2GR-FE V6: Camry V6, Avalon, Sienna, RAV4 V6, Highlander V6, Lexus ES350 and RX350. Six-speed front-drive transaxle, differential in the same case, one filter, no dipstick, and a fill procedure that trips up more DIYers than the wrenching does.
The Five Failures You Will Actually See
1. Lockup shudder between 35 and 50 mph
The number one complaint by a wide margin. Drivers describe rumble strips, or a vibration that feels like unbalanced tires but only shows up at light throttle on a gentle grade. It is the torque converter clutch slipping and grabbing in controlled slip, and early on it disappears the instant you add throttle or lift off, because either action drops the TCC out of slip control. With a scan tool, watch engine RPM against turbine RPM in that band: a healthy unit holds slip under about 30 RPM, a shuddering one oscillates 60 to 150. More on the driveability side in the Camry U660E shudder fix page.
2. Harsh or banging 1-2 and 2-3 shifts
Usually the SLT line pressure solenoid drifting out of calibration, or accumulator bore wear in the valve body letting apply pressure spike. A drifting SLT commands more line pressure than the unit needs, so every shift lands hard, and it worsens as the fluid heats up. Before condemning the valve body, clear adaptives and drive a full relearn. Any of these that has had a battery disconnect or a TCM reflash shifts like a dump truck for the first 30 to 50 miles and then smooths out on its own.
3. Delayed engagement into Drive or Reverse when cold
You put it in gear, count one, two, sometimes three seconds, and it clunks in. That is fluid draining back past a worn seal or a leaking C1 apply circuit overnight, and it is the earliest honest warning the unit is on borrowed time. Cold and only in Reverse points at the B1 circuit. Delayed in both directions with dark fluid means start planning the rebuild instead of chasing it.
4. Flare or a neutral feeling on the 3-4 or 4-5 shift
Revs climb between gears with no forward push. Usually the B3 or underdrive circuit losing apply pressure through a worn bore, not a burnt pack — at least not at first. Left alone it becomes a burnt pack, because every flare is that pack slipping under load and cooking itself. This is the failure where waiting turns a $900 valve body job into a $3,000 rebuild.
5. Speed sensor and gear ratio codes
The NT (input turbine) and NC (counter/intermediate) sensors sit in the case and read tone rings. When one drops out, the TCM cannot verify the ratio it commanded, so it throws a ratio code and defaults to limp. Sometimes it is the sensor. More often it is a chafed harness or a corroded connector where the case harness passes near the battery tray. Ohm the sensor and wiggle-test the harness before anyone orders a transmission — see our P0715 input turbine speed sensor guide.
The Codes, and What They Mean on This Unit
- P0741 and P2757 — TCC stuck off, and TCC pressure control performance. That pair is the fingerprint of a worn lockup lining or a lazy SLU solenoid, not a bad TCM.
- P0748, P0778, P2716 — pressure control solenoid A, B or D electrical. Ohm each at the case connector; the linear SL and SLU solenoids read roughly 5.0 to 5.6 ohms cold. Open or shorted means the solenoid; in-spec with the code still setting points at the harness or the TCM driver.
- P0715, P0717, P0793 — input turbine or intermediate shaft speed sensor circuit. Connector and tone ring first, sensor second.
- P0776 and P0777 — pressure control solenoid B performance or stuck on. Valve body far more often than the solenoid.
- A bare P0700 with no sub-code means you are only reading the engine module. Scan the TCM directly — half the misdiagnoses we see start right there. The full transmission code list covers the sub-code map.
Check These Five Things Before Condemning the Unit
- Fluid level, set the correct way. No dipstick. Level is set through the check plug inside the overflow tube with the fluid at roughly 115 to 130 degrees F, engine running, after cycling the shifter through every position. An overfilled unit aerates and shudders exactly like a dying converter.
- Fluid condition and the magnets. Toyota WS starts pink and darkens to amber. Brown with a burnt smell means clutch material in suspension. Fine gray paste is normal wear. Hard chunks or bright flake means stop — you are rebuilding, not chasing solenoids.
- Engine misfire. A 2GR-FE with one weak coil produces a shudder in exactly the same speed range as a bad TCC. Check fuel trims and misfire counters first. We have seen more than one of these replaced over a $70 ignition coil.
- Motor mounts. The passenger-side hydraulic mount collapses on high-mileage Siennas and Camrys and shudders under light acceleration. Two minutes with a pry bar rules it out.
- Battery and grounds. Low voltage makes solenoid drivers misbehave and sets intermittent electrical codes across the whole TCM. Load test before you believe any electrical code.
U660E Repair Cost Breakdown
| Repair | Parts Cost | Shop Labor | DIY Total | Shop Total |
|---|---|---|---|---|
| WS fluid drain and fill (single) | $60 - $110 | 1.0 - 1.5 hr | $60 - $110 | $190 - $360 |
| Pan, filter and full solenoid set | $180 - $380 | 3.5 - 5.0 hr | $180 - $380 | $700 - $1,200 |
| Speed sensor (NT or NC) | $60 - $140 | 0.5 - 1.5 hr | $60 - $140 | $160 - $400 |
| Reman valve body | $450 - $900 | 4.0 - 6.0 hr | $450 - $900 | $1,050 - $2,000 |
| Lockup clutch repair (unit out) | $300 - $600 | 8.0 - 12.0 hr | not a driveway job | $1,400 - $2,600 |
| Full rebuild, independent shop | $700 - $1,100 in kit | 14 - 20 hr | — | $2,400 - $3,600 |
| Reman unit installed | $1,900 - $3,000 | 8 - 12 hr | — | $2,900 - $4,600 |
| Dealer replacement, Lexus ES / RX | — | — | — | $4,800 - $6,800 |
The line that surprises people is the solenoid job. The pan faces down and the valve body comes out with the unit still in the car, so solenoids and a filter is a real repair instead of a teardown. That is why the diagnosis is worth doing properly: the difference between the right answer and the lazy answer here is about $2,500.
Solenoids, Filters and Kits — Ships Same-Day
Solenoid sets, filter and pan gasket kits, and master rebuild kits for this unit and its U760E sibling. If you need hard parts — drums, planetaries, pumps — our sister store CoreTransmissionParts.com carries the heavy stuff.
Shop U660E Parts →Rebuild or Replace: The Honest Call
Rebuild it when the car is worth more than roughly twice the rebuild price, the differential is quiet on a steady cruise, and the pan came out clean of hard metal. A 2011 Sienna at 160,000 miles with decent fluid is a good candidate. So is almost any RX350 or ES350 in sound body condition — those are worth enough that a $3,000 rebuild is easy math.
Replace it with a quality reman when you find hard particles on the magnets, when the front differential howls at a steady 45 mph, or when the pump is scored. A unit driven hard while slipping has usually taken out the pump bushing, and by the time you pay for the pump, the drum and the labor a second time, the reman was cheaper on day one. Any reman worth buying comes with an updated converter and a written warranty.
Walk away from the repair when the vehicle is a rusted-out Camry at 240,000 miles. A low-mileage used transaxle with a 90-day warranty is the rational choice there, and the labor is identical either way. If the car is on the fence, price the job against our Camry transmission replacement cost and U660E problems overview pages.
One note on the cousins: a four-cylinder Camry, RAV4 or Highlander has a U760E, not this unit — similar architecture, different valve body, different parts. Read the U760E problems and cost guide instead. The same discipline applies to the European units in this class: the 722.6 conductor plate replacement cost and the 09G / TF-60SN problems and cost pages.
Keeping One Alive
Toyota called the WS fluid lifetime. Every transmission shop in the country disagrees. A drain-and-fill every 40,000 to 50,000 miles takes five quarts, costs under $110, and is the difference between a converter that goes 200,000 miles and one that shudders at 90,000. Do not machine-flush a neglected unit at 150,000 miles — do serial drain-and-fills a few hundred miles apart and let it adapt. Use Toyota WS or a fluid explicitly licensed to that spec; universal ATF will have one of these shuddering inside a month.
FAQ
Is the U660E a reliable transmission?
Mechanically it is one of the better six-speed transaxles Aisin built, and the clutch packs routinely pass 200,000 miles. What fails is the lockup clutch and the valve body hydraulics, and both get far worse when the WS fluid is left in for life.
Can you fix U660E shudder with a fluid change?
Sometimes, if you catch it early and it only shows at light throttle between 35 and 50 mph. If the shudder returns within a month, or the drained fluid was dark with clutch dust, the converter lining is gone and fluid will not save it.
Does the U660E have a dipstick?
No. Level is set through a check plug inside the overflow tube at roughly 115 to 130 degrees F, engine running, after cycling the shifter through every position. Outside that window you get a false reading, and an overfilled unit foams and shudders.
How much does it cost to replace U660E solenoids?
A full solenoid set is about $180 to $380 in parts, and shop labor is 3.5 to 5 hours because the valve body comes off with the transaxle in the car. Most jobs land at $700 to $1,200 installed.
When is a U660E not worth rebuilding?
When there is hard metal in the pan, when the differential howls, or when the car is worth less than about twice the rebuild price. Then a warrantied reman or a low-mileage used transaxle is the better money.