This started intermittently but now it will only occasionally shift into OD. I let a Toyota dealer look at it and they said 'the overdrive solenoid in the valve body has an intermittent short'...they wanted $300+ for the valve, total of over $800. I've checked with a Lexus dealer and none of the 5 solenoids in the valve body is nearly that expensive...anyone know anything about this transmission or had this happen to theirs? I'm at 85K so I'm out of warranty. Thanks!

 

Is this happening when the engine temp is at it's normal operating range or when you first get in the car and startup?

If it's the latter, the electronic control will not allow it to shift into 4th aka O/D when the engine temp hasn't reached optimal operating range. This goes the same for any other Toyota/Lexus 4spd Auto ECT.

 

Thanks for your reply...I hadn't mentioned that it almost always shifts into O/D only right after starting up. I bought a $25 1yr subscription to AllData and found I could check the O/D solenoid on the wiring harness at the ECM. The O/D (S4) solenoid checked out fine with the car having cooled off for a couple of hours, and I could manually actuate it with 12VDC from the cigarette lighter and hear it click. But as soon as I drove it for a few minutes the resistance dropped from 13 down to 2 or 3 ohms and it wouldn't actuate anymore. So it's a short/open when the solenoid gets up to temp. Sorry for all the detail, but thought somebody might benefit from this sometime. I guess the next question is, has anyone ever replaced a solenoid in the transmission valve body? Does it take special tools?

 

No worries on the detail. If you're not too comfortable on taking apart the tranny, I would leave it to a specialist to replace the solenoid.