2006 MT 2.3 na
 

I'm sorry I should have been more clear... I have a MT car 5 speed.

Any other Mazda trannies the will direct swap into the car?
main reason is i use this car for traveling around Texas picking up motorcycles to flip. Doing just under 80 the RPM's are at 3800. That pretty high over a 10 hour ride.
the end result would be to have lower 5th gear rpm while doing 80ish.

if there is no direct swap... has anyone change the 5th gear ratio to better suit long highway cruising.

Isn’t the ‘06 model a 4 speed ATX? It might be possible to swap in a 2nd gen 5 speed ATX, but I don’t know what else would need to be changed for the newer transmission to function appropriately.

There are no optional gear packs for that transmission. Actually for Mazda transmissions there is only a couple available aftermarket all change for a close ration box for Road Tracking.

are the turbo models transmissions the same?
bolt patterns....
gearing....

i'm looking for MT(manual transmission)

I only did a quick search and aside form getting a custom gear set @aprox 4k you are not going to achieve the result you want. I suggest recalculate your ETA at a slower MPH.
I looked at your basic MAZDA advertised specification and IMHO you will not have the power to support a higher gear ration at a sustained speed you would be traveling at?

All said and done technically speaking the engine is well capable of sustained 3800rpm for several hours with out harm. Many engines are run for hours at the mechanical safe limits for over 48+(some over 120hours) hours or more during the development stage as well some engine testing was done under a simulated load.

what was the wording you used for searching. I really didn't find anything on the trans.
do you have a trans code name as a reference.

example.... mistubishi has engine code of 46g3 4g72.... and so on.