Chrysler Repair: 3-speed non-electronic autotrans problems, gear shift linkage, throttle linkage

Question
Hello, the answers you've been able to provide others have been impressive. Perhaps you can help me with my problem?

I recently acquired a 1987 LeBaron coupe with the 2.2l turbo and 3 speed automatic. Neat little car, and from I've read here and elsewhere it might be worth hanging on to, which brings me to my problem.

The seller said it had transmission problems, and sometimes wouldn't downshift when you pressed hard on the accelerator ("kick-down?"). He mentioned that he changed the trans fluid and filter but that didn't help.

I tried driving it and noticed it wouldn't UP shift into 3rd, but bought it anyway <gr>.

Driving it again taught me that at about 47mph and 4k RPM it would sometimes shift to 3rd. Or sometimes it would miss and end up completely out of gear. This was usually fixed by putting the shifter into 2nd or 1st and waiting for it to engage. Also, every so often, it would shift up to second fine, but then not back down to first when the car came to a stop. So I'd be starting in second gear. This too was fixed by shoving the shifter down to first and then up to 2nd.

The fluid level looks and smells okay. Doing the self-diagnostic check gave me codes 23 and 51 (which aren't specifically transmission related).

Any thoughts were to look next?

Many thanks,
Jeffrey

Answer
Hi Jeffrey,
It is refreshing to get a question about an old-fashion non-electronic transaxle. You should not expect to get any codes from the unit because it has no controller. It is totally hydraulic only, and is the A-413. In the turbo application it doesn't use the torque converter lock-up.
There are several possibilities that cause these shifting problems according to the manual:
hydraulic pressures too low
valve body leakage or malfunction
incorrect gear shift linkage adjustment
incorrect throttle linkage adjustment
governor support seal rings broken or worn
kick down servo band or linkage adjustment
governor malfunction
The clutches do not seem to be implicated so a general rebuild may not be in order. I have the pages on some of those adjustments and would xerox and mail them to you if you like, along with the diagnostic symptom table.
It costs me 8 cents a page but would be pleased to mail you them and have you send me back postage stamps to cover my costs.
On the codes that you did get: the 23 says the charge temp sensor is off-value (check to see is its resistance in 7,000-13,000 ohm at 70F, 700-1000 ohms at 200F, it is located on the inside of the intake manifold, near the fuel pressure regulator. The 51 code suggests the oxygen sensor in the exhaust may be shot because its voltage is too low.
So those are some suggestions.
Roland