So I took this Thursday off work so I could perform various stuff on my 99 Civic LX and figure out why it's running slightly sub-par. One of the things I notice is the way the transmission shifts. While it's certainly not BAD, it does act a hair funny. Sometimes it shifts a second late when accellerating, and sometimes it downshifts a second early when decelerating (imagine braking and then the car downshifting, causing a sudden, startling pull-back).

One of the things I planned on doing this Thursday was getting some OEM tranny fluid and draining the old fluid and topping it off with new fluid. However, I read that people should be cautious when changing out fluid, as it can actually hinder you if regular tranny maintenance hasn't been performed, especially in a car like mine with 120k miles. That said, the original owner of the car (who owned it for the first 110k and didn't sell the car directly to me, and thus had nothing to hide) had this HondaCare service from the dealer and swore up and down that they were always ahead of schedule on maintenance, and based on the immaculate condition of the car's physical appearance, as well as their sweet country charm (heehee), I believe them. Also, when I pull the tranny dipstick, the fluid doesn't contain any type of metal or plastic shavings that I can see, doesn't smell bad, and is a shade somewhere between pinkish / yellowish / VERY LIGHT brown... this is what I would anticipate in slightly used tranny fluid, but not 100k old tranny fluid.

That said, if you guys were me, would just just change the fluid? And if so, would you guys recommend any type of treatment that's floating around on the market, like Lucas additives, or would you just stick with the straight-up Honda tranny fluid?

Thanks a bunch.

 

I have read descriptions of the Honda Civic automatic transmission as "bad out of the box." Nonetheless, I think that if you drain the ATF and replace it with fresh Honda or Honda-recommended ATF, you will see an improvement in shifting. It's more expensive but, if you did this drain-and-refill procedure 2-3 times with driving the car in between (=flush), the outcome might even be better. Avoid the additives.

 

Thanks RonJ, your continued help is awesome as always. I read somewhere that this transmission holds 3.8 L (or was it quarts?). At any rate, if draining it causes fluid to remain in the pan, wouldn't it theoretically take even less fluid if I'm doing a drain / fill a couple times? I imagine I just drain the thing, then fill it into the same opening where the dipstick goes it, and keep filling till it reaches the top, then drive it around for a few miles and repeat?

 

Yeah, it takes ~3 U.S. quarts for a drain and refill. The procedure you describe is correct. Good luck.