guitarhero728

Hey all, I have a 96 Civic LX with automatic transmission and about 180k miles that I bought about two months ago. The car ran fine when I bought it but shortly after started having engine trouble. The small car dealer I bought it from was kind enough to put in a new (used) engine for me at no charge. All was good until yesterday when I noticed the transmission shifting a little rough, particularly when shifting from 1st to 2nd gear, and even more so when I give it extra gas and it shifts quickly. It makes a kind of thud noise when shifting, as I said particularly between 1st and 2nd. Also, I've noticed that the D4 light comes on for a little bit when I turn the key to ON without actually starting the car and if I remember correctly it didn't do that before a couple days ago. I checked the transmission fluid and it's full and not dirty. If I drive very gently then my car will shift normally but if I give it any sort of extra gas then it shifts rough. I also have noticed that it seems to take a little longer to crank the car but that may just be my imagination. Any ideas? Thanks for reading this.

strategy400

Your fluid probably is dirty. Flush it:

https://honda-tech.com/forums/showth...4#post47856634

guitarhero728

Found out they changed the trans fluid when they replaced the engine. Any ideas?

strategy400

Changed or flushed?

Manual says:

Harsh upshift 1-2. 12, 19, 20, 29, 50, 51, 57, 54
Some of these are "foreign material in <component>...". Worth attempting a flush. In every transmission I've ever flushed the dipstick looked nice and clean and the stuff that came out was black, brown and grungy. I'd try a flush with the correct fluid before tearing into clutches, solenoids and vavles. "They" (small car dealer?) probably poured whatever they had handy in if they even did anything.

tekfoc

Replace with 3 bottles of Honda ATF fluid only .
Never use nothing else .
Same goes for power steering fluid Honda only . For future reference .

strategy400

Yes genuine Honda fluids or prepare to hate yourself and want to die. I'd go ahead and flush all the fluid. A drain and refill only replaces 3 quarts where a full flush replaces all ~6-7 quarts. The dirty mucky fluid is hiding deep inside your torque converter, valves, differential and clutches. If you just drain the 3 quarts it will come out all sparkling clean but the dirty crud is still in there.