4th gear or OD

I did a search but really did not see this question asked.
i just bought a 05 Tacoma TRD Sport with a automatic transmission.
i have 20 miles of back roads before i get to the nearest interstate.
just wondering what gear most would use at speeds of 45 to 50 mph.
i have been driving in 4th so the tranny isn't constantly jumping back and forth from OD to 4th.

in 4th it runs right at 2k rpm. in OD it stays around 1.5k .
i know i would get better gas mileage in OD. but whats best for the tranny?
thanks for your replies. Shawn

 

unless you are towing leave it in drive, the hunting isnt going to hurt anything, and its likely not jumping between 4th and 5th, but more than likely simply locking and unlocking the torque converter in 5th (which seems like a shift)

 

I drive in 4th a lot around my place , low speed rural roads that are right at the point where the tranny locks / unlocks the TC as well as dropping from 5th to 4th

I feel this truck holds D too long , especially going up hills

 

Either setting is fine for the tranny. Just change the fluid at a sensible interval (i.e. not every 100k).

I use 3rd and 4th gear for comfort in the city. The engine braking is helpful in stop-and-go traffic.

 

I quite often drive mine around on 40 MPH roads in 4th. Seems to hold the torque converter locked in 5th way too long at those speeds.

 

I put my Trans back into "learn mode" and drove it like a rally car immediately after forcing downshifts with the throttle around curves and mild hills .... Now it's not going into OD so soon and downshifts come with very little toe in on the pedal or increases in load . Much happier now . May want to try it

 

so if your drive an auto while hunting or offroading is it better to leave it in low or 1st? i drive i 5 sp and dont know much about autos