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.

 

Your fluid probably is dirty. Flush it:

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

 

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

 

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.

 

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

 

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.