A-140 Toyota autobox problem in Camry

[M3 Mitch]

Not certain if you in the UK even call the large 4-door Toyota a Camry or something eifferent - anyway the daughter's 1987 Camry with A-140 autobox is doing the following:

If I lock out the overdrive, it shifts from 1st to 2nd normally, but never shifts to 3rd. If I put the shifter in 3, there is no engine braking in 2nd (which is normal), if I pull the shifter back into 2, there is no change in RPM so it's def. stuck in 2nd gear. If I enable the overdrive, when it should go to 3rd it shifts into a false neutral.

There are no transmission fault codes stored, which according to the manual means both speed sensors and both main control solenoids are electrically sound (I realize that one solenoid might well be mechanically stuck, and this would not generate a code)

I'm suspecting a valve stuck in the valve body - thoughts? This is based partly on a troubleshooting chart that says a failure to shift 2-3 can be a particular valve in the valve body. I'm trying to decide if I want to take the valve body out and clean, disassemble it, try that, or go to my friend's shop since if it's not the valve body likely the fix will be a used transmission from a breaker's.

Car has about 200K miles, fluid looks good. It did this stunt occasionally in the past but now it's doing it continuously. I have the factory manual and have done all the external adjustments.

[Deltafox]

Auto's are pretty complex, especially the valve block, so unless youre feeling adventurous.....

Probably best just to swap the box out for a known good replacement.

AFAIK theres no real electronics in those boxes, just two solenoids, a reed (speed switch) a switchblock (for p-r-d-n-l-1-2-3) and a speedo drive.

Easier to just swap the box imho.

[M3 Mitch]

Update on this - drove it to my favorite mechanic on about the hottest day of the year, 50 miles in 2nd gear, it wouldn't shift up even at say 4500 RPM.

Mechanic got around to driving it and it shifted normally. Although now from time to time it engages very softly and slips in Reverse or sometimes first gear initally. This problem goes away within just a few minutes but I wonder if it will be worse in winter?

My guess for right now is some foreign matter in the valve body, previously bothering the 2-3 shift valve, is now bothering the 1st and/or reverse actuating valves.

Utterly no symptoms of slipping once underway properly in either direct drive or overdrive.

For now it goes back to the daughter for a 2 or 3 week period, then back to me as she's moving to downtown Seattle where a car would be more a liability than an asset -

What do you guys think, worthwhile taking the valve body out (I don't know this is the faulty part, I suspect it but can't "convict" it) and taking it to a shop, or just make plans for installing a used transola from a breakers?

I find it hard to believe that any problem with the clutches etc. of the transmission proper could come and go like this, thus the thoughts about valve body or solenoid faults.

Any experiences or advice gladly received!

Mitch

[deltafox]

The camry has an ecu for the autobox that talks to the engine ecu and the cruise control ecu also.
It may be worthwhile pulling the plugs on the autobox and checking the connections (usually very very reliable tho) just in case one is loose/corroded/chafed/ing.
Im pretty sure you can interrogate the autobox ecu, but it does depend on what year.

Apart from that, the easiest option is to replace the valveblock/solenoids with known good items or simply replace the entire box.