Hello,

Sysptoms are; Five minutes after driving, transmission will not go into OverDrive. If I stop and turn engine off, then it will work for awhile.

Just toke my RX 300 99' 171,000 miles to have the transmission fluid /filter replaced. Serviceman called and said he could not find anything during Diag. so he assumes the OD problem could be internal...meaning a new trans is in order.

Serviceman says; The computer could be sensing lack of pressure when OD is reached and denies the request. This keeps the trans from burning out!!!!!!!

So he thinks he should replace the trans. But, he does not rule out the computer. Deeper diagnosis is needed.

Should I have a second opinion?
Any options??

 

Do you have a check engine light on? If so, do you know the codes? It is amazing how many posters (along with their mechanics) don't realize that a CEL for an unrelated engine problem prevents the tranny from shifting into overdrive. This is by design. Or is it a trans failure code?
Assuming that you don't have a CEL on, did the problem just happen all at once and then you went for the fluid/filter change or was it possibly caused during a routine fluid/filter change?

 

Yes, CEL light is on. Serviceman mentioned 3 codes that did not relate to Transmission.
P0171 - bank 1 Lean
P0330 - knock sensor # MFunction
P1305 - ignitor bank 2 sensor

He says computer disabled overdrive

 

He is correct. The computer disabled overdrive due to one or more of your engine codes. Most, but not all, engine related codes will do this. I bet overdrive stopped working at the same time that your CEL came on. Fix your engine related codes and reset your CEL and your trans will work fine.

 

I've heard the P0330 code will disable the OD. Also, I've also heard that severe cold temps causing this until the ATF warms up.

 

Before you fix the knock sensor (that is the key code), what kind of gas are you running right now?

 

I had been trying different gas stations.. I use Unleaded Plus... Something said in my mind that (knock sensor) referred to possible bad gas....no pun intended! Now i'm back using Chervon

 

Chevron (and Sunoco) are really the only two gasolines I will touch now, but except for a few experiments, I only run Super. I'd run the vehicle with some Super first for a week and then see if anything improves. If not, I'd replace both knock sensors (it's a PITA job at it's best to do both), http://www.findonefindall.com/toyota...ock_sensor.htm

 

Well.. I have taken the RX in for the knock sensors today...$800plus. I tried driving to work today and every time I stopped I would lose ovedrive. I was turning the car off for 10 minutes at a time. Very frustrating!!!! Bought Techron to possibly eliminate knock sensor prob per suggestion. Mechanic says it won't help, bought meter also to reset codes.

 

I am not sure what you are trying to say here. Did you have the knock sensors replaced and you are still having the overdrive problem? If so, do you still have a CEL? What are the codes?

 

Sorry for the confusion, Knock sensors haven't been done yet. I was trying to get someplace prior with much frustration. Work is being done on Tuesday. Any suggestion for the code; P0171, I see it twice on the meter. I get three codes
1. p0171
2. p0330
3. p0171

 

Don't worry about P0171, that usually pops up when A/F sensor issues show up and even knock sensor codes. The P0330 is the one to focus on for the time being.

 

Hello,
Thanks for the help on the Engine code (P0330). All fixed and runs great. Now I'd like to ask advise on the other engine code (p0171).
Although if doesn't seem to affect anything, will it keep me from passing smog in the near future?

 

I take it P0171 is still in the codes?

 

Code P0171 (bank 1 Lean) Yes! When I view the codes P0171 is the only one remaining.