98 Honda Civic TCC – OBDII code P0740

In April 2012 I changed my Honda transmission fluid for the first time to my knowledge. It’s a 1998 Honda Civic EX A4RA FWD automatic 4spd 1.6l Vtec. I was at 135,000 miles. The fluid did not stench but was a little dark. The magnet had no accumulated metal shavings either. Was a little thicker and off colored but not as I expected it to be. I was having some noisy hesitant shift between 3 and 4. This fixed that issue.

In Nov 2012 my car began not “locking up” TCC when cold and not until fully at op temp and fuel economy dropped drastically. A slow decline until it just never would go into the final “lock up” phase of shift. This threw a code of P0740 Honda OBDII. I researched this and continued to drive the car to and fro keeping it below 60/65 or rpm lower then 3k. (bout 300 miles a week) Few thousand miles further and the “lock up” started again and the engine lite went out on its own. Few thousand miles further it all started again and my engine lite was glowing. Few hundred miles later the engine lite went out and started shifting all the way thru lock up working correctly. Finally in early 2013 the system failed again and has not come back since.

I checked tranny fluid level, ok, fluid looks premo. I am sitting at 167500 miles. I narrowed it down to the TCC Solenoid Circuit A/B. Removed the factory part and tested it first with jumper applying voltage to both terminals definitely hearing the click of the open and close of the valve. Then tested the terminal for resistance readings. Here is my confusion. The tech manuals state that the terminals should each have a resistance of 12 to 25 ohms if above or under it’s bad get a new one. Mine tested resistance at 32.7 ohms. (But the valves opened and closed with voltage applied). So, I purchased a used solenoid that was said to be bench tested good. When I received the part I bench tested it myself. I got resistance readings of 30.7 on the terminals and when voltage applied the “click” of the opening valves occurred. My assumption, this one was bad too. I put it on the car anyway to confirm. With this new/used part my car shifted funny, shift pattern changed, 2 into 3 was very short, jump odd jumping rpm were lower at 60 mph but never did “lock up”. This threw engine lite with six codes two being the normal P0700 and P0740. One said confirmed. Apologies I do not have those codes now. I removed the part and returned it to the seller (quite a battle but I won).

Still convinced this was the solution, I then purchased a new Honda part and put it on the car. I did not test the part as “assumptions” coming direct from Honda would not need to. Drove the car 100 miles up and down thru the gears and at somewhat higher speeds. Within minutes the engine lite was back on and has the same two codes P0700 and P0740. And now there is a odor of “hot”.

In reading up there are so many opinions voiced from professionals I’m uncertain my next move. I have priced rebuilt transmissions for my car .. more then I can afford at this time. I have considered changing the fluid AGAIN or some suggested having it machine flushed against Honda’s recommendations. I have considered rebuilding the tranny myself .. books and late nites .. no experience here. I am aware that if I don’t do something I will burn up my transmission and need to replace it anyway. Anyone else encountered this problem and solved it without transmission replacement.???? Please help. Am I looking in the wrong places ?? Is there anything more I can do ?

Thanks for any advice.