U660E Archives - Transmission Digest
Toyota/Lexus U660E/F, U760E/F Oversized C2 Apply Control Valve Kit

Toyota/Lexus U660E/F and U760E/F transmissions may exhibit 3-4 shift flares, slipping in 4-5-6, and burnt C2 clutches due to wear in the C2 apply control bore. Sonnax oversized C2 apply control valve kit (p/n 47740-63K) restores the necessary hydraulic clearances required for proper valve function while protecting against premature wear.

Toyota U660E

The Toyota U660E is a front-wheel-drive six-speed used in a variety of applications. One issue that surfaced early on had to do with the case and counter drive gear bearing. It is important to validate what is worn and know what repair options are available before pricing the job.

Toyota/Lexus Oversized Converter and Lube Relief Check Valve Kit

This new Sonnax product is made to re-establish correct clearance for converter and lube functions.


The owner of a 2008 Toyota Camry with a 3.5L engine powering a U660E transmission brought his vehicle in to Deltrans with hard shifts. Bill Harris road tested the vehicle to verify the complaint. In doing so he not only verified the owner’s complaint, he also discovered that it did not shift past 4th gear.

Two Unique Situations, Two Happy Customers

All of our initial diagnostic evaluations include a battery and charging system test. I’ll bet you can guess the outcome of this one; the battery failed, but the alternator had passed. At this point we informed the customer that some electrical testing was going to be necessary in order for us to find out what was causing the problem. The customer agreed to that and we then proceeded with the job.

Use TSB’s in Your Diagnostic Routine

When diagnosing today’s complex vehicles, we have a wealth of information at our disposal. How we use that information is crucial in making the correct diagnosis the first time, every time. In some cases the diagnosis may be cut and dry (fluid is burnt, the pump is whining, and the vehicle will not move). In other cases, the diagnosis may not be as easy, or worse; we may “think” or “assume” we already know the problem.

Toyota’s U660E Flex Lockup Control

Toyota’s six-speed U660E (Figure 1) uses a converter-clutch strategy called flex lockup control. A partial explanation of this flex control strategy by Toyota follows:

During acceleration, flex lockup-clutch control operates when the transaxle is in second gear or higher and the shift lever is in the D, S6, S5 or S4 range position. During deceleration, it operates when the unit is in fourth gear or higher and the shift lever is in the D, S6, S5 or S4 range position.