Toyota Repair: 03 4Runner Transmission Issue, o2 sensors, catalytic converters

Question
QUESTION: I have a 2003 4Runner and about 6 months ago I had fault codes that resulted in me changing 2 of the shift solenoids.(not cheap!) Recently, more fault codes. Took it to a shop this time. Same result; replaced two solenoids = more bucks. One problem this time is that it would not shift into overdrive. The problem went away when I got it back from the shop but only for a couple of days. Codes came back on and it stopped shifting into O/D again. So, on a whim, I cleared the codes again and it started shifting into O/D again. The shop told me that they fixed what the ECU said so i'm out there. I'm wondering if the truck has a transmission ECU and/or has there been other people that have had similar issues. Is it the ECU, the transmission ECU, or just mechanical?
 Help?
      dhyland

ANSWER: I need to know the code numbers that you are referring to. The transmission ECU is part of the ECM on this truck.Were the same solenoids replaced twice or were they different this last time. Is the only problem now that it won't shift into O/D?

---------- FOLLOW-UP ----------

QUESTION: One code is 430. A local exhaust shop said the platinum coating on the pellets in the catalytic converters is wearing off and it's making the O2 sensors not read enough heat. Any truth to that? Anyway. the other is 771. Shift solenoid stuck open. That's what the shop read too and POW! $850.00 later, same problem. When I clear the codes, it shifts fine. It slips accelerating into 1st and when I roll into reverse.
Thanks for any help.
  dhyland  

Answer
The P0430 code is a catalityc converter code so that sounds about right. The 771 code is a shift solenoid "e" code so it sort of made sense that they replaced the solenoids but it didn't fix the problem, there are two possible things left that the repair manual states, either there is a problem with the valve body or the transmission itself is starting to develop an internal problem, how many miles are on the odometer?
In my past experience replacing solenoids usually doesn't fix the problem because there are metal particles in the fluid that restrict these solenoids causing them to stop operating. The particles usually come from internal transmission components that are failing.