I recently picked up a 93 Wagon with an automatic. The original transmission was replaced with a used one at approximately 340k, supposedly from a car with approximately 60k miles.

Sypmtoms:
1) When approaching a turn-in, such as a driveway entrance, or turning down a side street, but *not* completely stopping, I will give the car gas coming out of the turn, and it acts as if it's revving in Neutral. Not knowing Hondas, I would compare it to a car where the Torque Convertor is disengaging completely. When I it revs for maybe 1-2 seconds, then goes like it should.
2) Seems to 'search' or 'hunt' when it is going between 3 & 4.
3) Periodically, the 'D4' light on the dash will not come on when the car is started. Some of these times, it will come on after I have driven the car a bit. Sometimes it doesn't. The car drives the same whether the light is on or not.

I've heard and read that the TCU on these cars has a habit of failing. The Previous Owner replaced the TCU with a used unit. While this used unit is still under the seller's warranty, how can I diagnose if this one is in fact bad?
I also had someone tell me that the revving when turning thing could be anything from a weak spring, to a blocked spring, to bad solenoids, to the TCU.

Best place to start, advice, or...?

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93 Accord EX Wagon
Automatic
342k+ Miles
It's Green....
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Have you checked fluid condition? Is the fluid burnt or dark? Or is it clean and transparent red? If its burnt or dark then you know that you have more than a TCU issue...Where was the trans purchased?? Don't see to many older accords with 60k on them...unless they used a Japanese imported trans?? Did you buy it with a known transmission issue or did it come about after the fact?