07 Auto Trans Not Shifting Smoothly 4th>5th

jds0912

Adventurer
Hello there. I have had my 07 TRD OR for a few years now and noticed a problem shifting about 9 months ago and it is getting worse. I find that when shifting from 4th to 5th (auto trans) the truck seems to hang out in 4th gear until around 2500+ RPM before reluctantly dropping into 5th. I found that if I knock the shifter to the left and then back into D it will immediately change gears. Problem happens mostly on slight inclines, like merging onto the highway, and getting into highway speeds. Seems to lessen after driving for a period of time.

This problem is probably contributing to my bad gas mileage (275 mi/tank) and is potentially effected by some codes I've thrown for a little while as well. My check engine light came on not too long ago and when I ran the codes I got 1-2 bus 02 sensor problems. Since then I have cleaned the MAF and throttle body, changed the plugs and the battery, but still get the check engine light.

Do you think that the 02 sensors are bad and are contributing to my shifting problems (trying to warm up the engine by staying in OD)? Or are the two problems unrelated. Either way, I'd love to figure this out soon. Thanks for reading through this.

/disclaimer: I have not been as proactive about this as I should have been, and the problem is likely getting worse due to my negligence.
/2" lift, 255/75 tires
 

Mrknowitall

Adventurer
The behavior you're seeing has nothing to do with the internals of the transmission. It is doing, what it is doing, as part of a safe mode. You currently have an emissions related code set in the ECU. That means the vehicle will do all sorts of weird things (like refusing to go into OD as expected) in order to maintain "safe" emissions. This also likely means richer calibration, which keeps the catalytic hotter (to clean up everything). Get your engine code fixed and then reset everything. Drive nice while the trans re-learns your habits.
A trans flush can't hurt,especially on a 5yo truck, as long as its being done with the right fluid. Some shops like to cut corners and run with a machine half full of cheap Mercron. Amsoil and Mobil1 trans fluids are both "type-T" approved, or you can, of course, buy actual Toyota ATF.
 

jds0912

Adventurer
After the transmission flush, you might want to try a zero-point calibration. Not sure how likely that will help, but worth a shot. I believe it affects shift points, and it's free..

http://www.toyota-4runner.org/5th-g...celeration-sensor-zero-point-calibration.html

I have an 05 with 110k on it. Tranny has been flushed twice with OEM Toyota fluid, it was dark and dirty each time.

Maintenance is worth every penny.

The behavior you're seeing has nothing to do with the internals of the transmission. It is doing, what it is doing, as part of a safe mode. You currently have an emissions related code set in the ECU. That means the vehicle will do all sorts of weird things (like refusing to go into OD as expected) in order to maintain "safe" emissions. This also likely means richer calibration, which keeps the catalytic hotter (to clean up everything). Get your engine code fixed and then reset everything. Drive nice while the trans re-learns your habits.
A trans flush can't hurt,especially on a 5yo truck, as long as its being done with the right fluid. Some shops like to cut corners and run with a machine half full of cheap Mercron. Amsoil and Mobil1 trans fluids are both "type-T" approved, or you can, of course, buy actual Toyota ATF.

Thanks folks. I'm gonna flush her once it warms up a little bit. Mrknowitall, thanks, that was the feeling I had with the problem. I'm going to sort out the codes this weekend and hopefully my truck will be healed soon. I'll report back.
 

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