Has anyone noticed this to happen? would changing these fluids have any effect on miles per gallon? i seem to be driving in the same fashion, i.e speed/acceleration, but since i got the change about 3 weeks ago, I seem to be getting 1-2 mpg more.. i mean it's not much, but that's another 15 miles before you have to fill up again.. I might be totally off base with this and it might be that I my driving habits have changed.. i dunno, just wondering..
thanks

 

1-2 mpg is insignificant. You probably see more of a change if you drove in the mountains versus drove at sea level.

The only way changing fluids would help is if you hadn't changed them when you were supposed to, then changed them. Like, you hadn't changed your oil for 6000 miles, then changed it. You might see mileage go back to where it should be.

 

thanks.. that's what I figured..

 

Could not tell;I changed gears at the same time.!!!

 

As already mentioned, that is not a statistically significant change in mpg. You can't say with any degree of certainty that your latest mileage calculations were done during a period of driving that was exactly the same as the previous mileage you are comparing it to.
You might realize slightly better fuel economy if you had changed to fluid that had a lower viscosity.

 

I jus bought my 2003 with 40k miles, im not sure if the last owner ever chnaged the tranny or diff fluid. Could this be a problem? I will change the diff and tranny to probly redline mt90. Thats the correct one right? Which do i use for diff and which for tranny, i live in florida btw so it doesnt get cold.

 

Mt 90 for the tranny,and 75W90 for the diff.

 

Your tranny fluid is probably in need of changing but should still be OK. The diff fluid, however, is a bit different. It's probably turned to goo if it hasn't been changed.
The tranny and diff take different kinds of fluid, so no, you can't use MT90 in both. The diff fluid should be rated GL-5.

 

i realize that the mpg difference was insignificant, I guess my main question was can a diff/tranny fluid change have an effect of mpg.. which looks like a no.. or minimal if any.. but thanks for the input.. i'm not sure what the previous owner had.. i purchased it about 7 months ago with 19k miles, so I'm thinking he had Honda provided fluids.. I chenged the diff to Mobile 1 (only one at my local autozone) and honda mtf for tranny..

 

are the diff/tranny fluid ez to change? Any dyi thread on changing it?