Need Transmission Help!

Hello everyone, I have a 05 Tacoma V6 prerunner with a 5 speed automatic trans 135,000 miles. I'm having issues with it not going into Overdrive. From a dead stop I then accelerate and it shifts just fine through all 5 gears and when I get up to highway speed it doesn't drop down the rpm's, like it did before when driving at higher speeds. I have no codes popping up, and oil was changed 8k ago. I researched that there is a overdrive solenoid, do you guys think that it may need to be replaced? I do have experience working on vehicles and would like to fix it myself if possible, I just don't know a lot about transmissions. Would like to get people's opinions on it before diving into it. Thanks.

 

What oil was changed? Engine oil.

The transmission uses a hydraulic fluid not really oil.

Have you checked the transmission fluid level?

I would start there.

 

Here is link to Drain/Fill.
Read down to the part about Temp Check Mode. This will need to be done to properly heck the fluids.
https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

Thanks for responding, I had the dealership change it, so it should be all up to level.

 

I wouldn't be betting the farm on that assumption if I were you.

Use the link above posted by TnShooter and check it yourself.

 

Hey guys, an update. Checked oil level a while back, look's good. Had Trans shop check it out, they said the OD is working fine, their scanner is saying that it's going in and out of OD, and all gears. Can someone help me out and tell me what their RPM's are at at 55 mph, 65 mph, and 75 mph on level ground? I have a V6 auto. Man, it just seems like it's running too high on rpm's to me, I really thought the OD was out on it. Thanks.

 

Your tire size make a difference.
You can use the formula below to see what it should be

 

Sorry for the delay.
I took some pics. I just forgot to post them.

 

It's actually a common issue, not limited to my truck. I usually shift into 4 and then back into D when it happens. The RPMs will drop. But yes, very annoying and my trans fluid was changed at the dealer too with 100,000 miles.

 

OP, you will the torque converter unlock then drop to 4th. Or it will drop to 4th if you press the gas hard enough.

Maybe you are witnessing TQ Unlock/Lock.

Take a look at my pics for comparison.
Best of luck to you.