I have an 89 prelude si with an automatic transmission that will not shift into third.....while it is cold it won't shift past second gear,...after it warms it shifts directly into fourth from second....will it require a teardown to fix?...
I'm not sure about that version of Prelude, but on some 4th-gen Accords (1990-93), those are symptoms of a failing tranny control unit (TCU). The tranny itself is usually OK.
No, the transmission control unit is similar to the ECU and is normally mounted in the passenger compartment. Dunno exactly where in the Prelude, though. Wrecking yards are often good sources of ECUs and TCUs. A good price is on the low side of $100 US, with a 30 day warranty... enough to determine whether it is working right. If it makes it for 30 days it should last the life of the car.
I agree it sounds more like the TCU than the tranny - it's just doing what the TCU tells it to do.
Mike
On my '88 Prelude the TCU is under the carpet about where the passenger's left toes would be. You might even notice a little flap of carpet there kept in place by a strip of Velcro. You can peel that back and have a look at the light-emitting diode which flashes if the module detects an error. Watch the lamp while turning the ignition to the On position. Count the flashes. Any number greater than zero means the TCU has detected a problem (external to itself).
If your S3 indicator on the dash is not flashing (and I'm sure you would have mentioned it), you might still have a failure indication stored in the computer.
-- Chuck
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