I have the following CEL on my 2003 RX 300
p0766 (3 times) and p0741 - the p0766 says solenoid b & d - is this something that can be fixed by myself or does is need to go to a transmission shop? The car would act like the trans was slipping, rpms would spike and car would move accordingly. did it for a few miles then stopped, got in it the next day went about 15 miles down the road and all dash lights came on. O'Reilly gave me those codes and the reported fix is replace solenoid or transmission - two very different options. Any help would be greatly appreciated.

 

You could try a transmission fluid drain and flush. Sounds like dirt has got into the solenoid/actuator. I believe the solenoids are inside the transmission but others can confirm.

 

So I got the results from a transmission shop. He said that the 3rd gear clutch is out and that I have to replace the tranny at a cost of $4000. Can I replace the tranny with a used one from another vehicle? He said something about the tranny being computer matched to the vehicle and that you can not just put any tranny in the car. Is there any truth to that? I can find a used trans for any where from $400 to $1500 which is a big difference in price.

 

Was that $4000 for just the transmission or included labor?

 

yes, the transmission has to be matched to the computer. The ecu in some cars have tables built in to calculate the gear load so it can mix the air/fuel correctly. Other cars have a separate transmission computer that works in conjunction with the engine ecu.

As long as the pinout on the transmission matches the plug on your engine harness, you should be good to go as long as the replacement transmission has the same gearing as your original setup.

 

$4000 was transmission and labor

fastnoypi - would whoever I purchase a trans from know if its compatable by the VIN number?

 

I don't think the Lexus VIN has any indication of a transmission type by the VIN, but they can get the engine code and series grade and country designation. It might be possible they have some sort of cross reference database that might give the vendor useful info to match your RX.

According to the wiki, the first generation only came in 4sp auto. However I am uncertain if they had different transmissions available because a 2.2L and a 2.4L was marketed overseas.

An educated guess would be to ask the vendor if the transmission came from a 3.0L V6, to be on the safe side especially if your vendor source is a salvage importer.

For the 199-2003 RX300 AWD, the transmission code is U140F
If you have a FWD model, you will have to confirm the code. ..i believe it is the U140E

Be sure to pick the correct one or your transmission may shift funny due to the different final drives.

 

Thanks for all of your help guys!

 

I'm having Issue with my rx300 as well. Code reads p0765 solenoid malfunction. Anyone knows if doing a transmission flush will fix this problem. Pls lmk. Thank you .