nicodoni

Hi. My name is Nicolas and I am from Argentina.

I bought a 1993 Honda Accord SE AT a few months ago. I new that I have to spend some time (and money) to put some things in order.

The first thing to solve was that the speedometer didn´t work normaly and the “D4 light” blinking. I just replaced the speed sensor and problems solved.

Now, it is time to face the next issue: the automatic transmission works correctly when using the car in town, at low speed. All gears go through on a right way: they change up smoothly one to the next one at 2000/2200 RPM aprox. But when I drive on a highway for just a short period the gears start to fail. That is to say that changing gears (2° to 3° and 3° to 4°) pass over 3000 RPM. And this situation remains until I stop the car for a time.

The only thing I can suppose is that something is affected by the heat generated when the car runs at a high speed, but that is my limit of understanding (LOL).

So, what do you think is the reason of this problem..? Lock-up solenoid..? Shift solenoid…?

Thank you in advance, and sorry for my english.

MAD_MIKE

If the upshifts feel weak at higher rpms, and it affects all gears, I would suggest looking a the throttle valve cable that connects between the throttle body and the lever on the front side of the transmission.
Use a 12mm open end wrench to adjust.
Loosen the cable so there is no tension on the lever.
Push down the lever to make sure it is fully seated.
Adjust the cable to take the slack out, but do not put any tension on the cable as well.

If the problem is that the transmission goes into neutral, you will want to check a few things.
First verify that the transmission if full of fluid.
Place the transmission in every gear to charge each circuit.
Then quickly pull the dipstick, wipe it clean, reinstall the dipstick and then pull it out. The fluid should be within the hash marks, I prefer to keep it closer to the top of the hash mark.

If the problem persists, and the transmission/car has over 100Kmiles, and the fluid has never been changed, it could be the sump pickup screen is becoming impacted with debris. I would highly suggest draining, refilling, driving through all 4 gears, then drain and repeat the same process two more times to try and get the most of the gunk and debris out of the pan.