New Tranny = Better Gas Mileage?
 

I recently had the transmission replaced in my 2005 RX-8 at around 1600 miles because it started making a loud ticking/grinding noise when the car was in gear. (Yes, it is Sunlight Silver. No, I still don't believe in the curse).

Before the transmission replacement I average 17.7 mpg. After the transmission replacement, I am getting 19.8 mpg. I don't think that my driving has changed at all, but I appreciate the 2.1 mpg bump.

Is it possible that a transmission change could have such a pronounced effect on gas mileage?

i doubt it. I noticed a 2mpg gain over the past week in my car, and i'm pretty sure it's because it got warmer out the car doesn't have to idle high for as long.

Are you in a northern region? Did they swap out the oxygenated winter fuels for summer blends in your area the past two weeks?

Are you AT or MT?

The increase is interesting and it *could* be related to the transmission, but there are other, more obvious possible causes too.

It's an MT and I live in Dallas, so I don't think it has to do with a change in fuel blends.

Also, since getting the car back, I've been running the A/C (it got to 101 here yesterday!), so the increase is probably even greater in absolute terms.

I don't think that it has to do with decreased idle times, since it really hasn't been cold since I got the car in February.

The temperature here sky-rocketed a few days ago.

hey, from the time before your had to change your tranny, were you driving a little hard at the time. like flooring it and test out the car all the time. do you drive on the high way alot or city roads more.. tranny have nothing really to do effect towards your mpg.. the only time it would is if you're flooring and shift high rev.. but that wouldnt be anything related to your tranny... take a look at those.. maybe its your answer..

I believe this is more true then we know, of course i cant give you any examples of mine because i was doing them all subsonsciously..

In other words, im with abbid on this one.

This is weird. I have an 05 that just past 1,600 miles, the tank is not empty yet but I know exactly how many miles I hit when the gas gauge shows 1/4, 1/2, 3/4 a tank. Since hitting 1,600 at the 3/4 mark I have gotten more miles on the car when I hit 1/2 and 1/4 I'm guessing 2 mpg better. I won't know for sure till I fill up and don't want to jump the gun until I have more data. At first I thought it was the seasonal gas but at the ¾ mark the miles were normal. When I have more data I’ll post if it really did increase.

That's not it. I drive pretty conservatively, mostly on the highway in moderate traffic.

Actually, the week after I got the car back, I drove it harder than usual because I was so happy to have it back (after 2 weeks with a Mazda 3, yuck).

Forget what I said, just filled up and the mpg only went up for 11.5 to 12mpg. still sucks and so does the gas gauge.