4.0 automatic high RPM cruising

I just bought this truck last week. It's my first Tacoma. 2008 TRD sport 4 door long bed with 125k miles. I test drove it in town and never got it faster than 55. Now that I've been able to cruise on the freeway, I've found that it cruises at 65 MPH at 3,000 RPM, which seems high to me. It's definitely in 5th, I've counted shifting several times. Tires are stock size. It seems to run great, and the shifting is smooth. Only problem is the seemingly high RPM. RPM seem high is every gear. when I shift it to 4, it hit's 3,000 RPM at around 50 MPH. Idle seems normal

One weird thing is it has a green light on the instrument cluster "A-TRAC". It is on when the lights are on, and off when the lights are off. I've combed through my owners manual, and there is no mention of A-TRAC. I bought the truck private party and it has a clean carfax.

Any help is appreciated. Thanks!

 

Are you some how in 4WD.
I don’t have A-TRAC, but I didn’t think it came on unless you are in 4WD?

 

That's about 1000 rpm faster than my truck at those speeds. I can think of 2 possibilities.

If the previous owner had larger tires on it, and recalibrated the speedometer to match, and then went back to stock size before selling it your speedometer could be showing you driving 3-10 mph slower than you really are. It would depend on how much bigger the tires were. If this is the case you could be doing as much as 75 when your speedometer says 65. Check the speedometer with a GPS to verify accuracy.

The previous owner may have regeared to a lower gear ratio. In that case 3000 rpm at 65 would be about right.

Or it could be a combination of both.

 

I have switched into 4wd and 4wd low a few times and everything seems to work well. I don't think it's in 4wd now because I can turn the wheel all the way and it turns normally. To be honest I didn't think A-TRAC was introduced until after 2008, so I'm perplexed. Another weird thing i just found is the buttons on the left are fake buttons, but have wires that go to them. they just don't plug into a real button.

 

Seems like they must have re geared to a lower ratio. I used my GPS yesterday and found the speedometer to be off by only 1 MPH. Thanks for the response. Now I just have to decide if I want to keep driving slow on the freeway or gear it back to stock. Or I guess I could get bigger tires to compensate a little.

 

Call the guy you bought it from and ask him.
Again sure its in 5 th and the converter is locking up (you feel it and see rpms drop). Suggest manually going thru the gears slowly with shift lever and verify 5th and converter lock up as a simple starting point. Stock tires are 265/70r16 if TRD I believe and door sticker tells you so you can see if tire related.

 

This. I'm betting that you are not getting into 5, but are thinking the shift to fifth is actually lockup in 4th.

The reason being is the atrac light. This will only light up if the 4wd ECU thinks it's in 4low. And in 4low the trans will not shift into 5th.

I'd try sifting down into 4low turning off atrac and make sure the light goes off on the dash. Im betting one of the sensors on the transfer case is stuck or messed up and cycling it might help.

 

Doubt it's been regeared for larger tires. There will likely be signs of a lift, CMC etc... if that was the case.

 

08 TRD Sport doesn’t have A-Trac

 

Correct but OP stated that "One weird thing is it has a green light on the instrument cluster "A-TRAC" Which makes me wonder if the 4wd ecu is getting a funky signal or if it is infact an 08 trd sport. haha.

 

Maybe I’m using the ratio calculator wrong?
But 3k rpm at 65 mph is equivalent to 5.88 gears.
It should crawl for sure in 4Lo.

 

OP, if you want to know your gear ratio, you can follow the steps in this link.
You want to do the test for the Posi Rear End.
https://shiftsst.com/blog/post/how-to-determine-the-rear-axle-ratio.html

 

OP needs to figure out if hes actually in 5th or just 4th lockup. 65mph at 3k rpms is exactly 4th gear lockup with stock gears.

Simple test to simply put it in L and work your way up the gears.

 

Boom

 

Thanks for the responses everybody. I was able to jack up the truck and determine the gear ratio. It seems to have posi, as both tires rotate in the same direction when I turn one wheel. The drive shaft rotated just under 4 times for one turn of the wheel, which I believe is stock gearing. I also started in L and shifted all the way through fifth. It does seem to get into fifth, but maybe I'm missing something. I cycled into four low a few times. A-trac stays lit no matter what. There is no button or anything to turn it off. The are 3 wires that go into the blank plastic "buttons" instead of actual buttons. Tires are 265/65-17, which is stock. Out is a 2008, confirmed by the VIN, so I'm not sure how it has A-trac

 

ATRAC button should be in the center console by the cigarette lighter.

Maybe it’s the same dash for every truck and you’ve got a short circuit or something that’s lighting up the ATRAC light.

 

2005-2008 TRD Sport came with a mechanical LSD rear differential. If you put it on jack stands and spin one rear tire the other tire should still spin in the opposite direction.

If you want to see what options your truck shipped with go to


Https://www.toyota.com/owners/my-vehicle/vehicle-specification

And type in your VIN. Also, what's your door code? That will tell you gear ratio and if it's open/LSD/ELock

 

I have to agree. I don't think you're in 5th. The torque converter will lock up in 4th. That's what you are feeling.

With a 265/70/17 tire I'm turning about 2100 rpm at 70 mph

 

So here are 2 pics of what should be there (2009 pics) so would guess lacking the switches plugged in is at least one of the problems. Look under the Tacoma drivers side front side of rear diff and see if you have the locker it is obvious and has a wire to it (added pic at end). If you do you are missing the switch.




A-TRAC - Active Traction Control. While you have to manually turn this feature on and off, once it is on, it automatically detects wheel spin and distributes torque between front and rear wheels to suppress unnecessary wheel spin and control skidding. A-TRAC detects when one or more wheels have lost traction and automatically applies the brakes to the wheel with no traction, allowing it to send power to the wheel with traction. In order to activate A-TRAC, you must first put your vehicle in neutral, shift into 4LO and press the “A-TRAC” button. Only works under 3 mph in 4 Lo. A-TRAC is a stronger version of TRAC and does not involve cutting power or ramping the throttle down.

RSCA - Roll Sensing Curtain Airbag and it allows you to turn off the sensor in the side curtain bags related to roll over (Side collision still is activated). Intended to be used in off road situations involving a high degree of sideways slope

DAC - Downhill Assist Control and the system keeps the speed of the car below 15mph. Working alongside the ABS and traction control, it constantly monitors and adjusts the amount of power and brakes applied to each wheel, allowing for the car to safely negotiate difficult terrain.

RR Lock is the e-locker that only works in 4 lo and connects/couples the 2 rear axles together and when on disables operation of ABS, VSC, TRAC, DAC, and if you have Hill-start assist control (HAC). Dash lights show them off. Note that A-Trac if on works with the rear locker up to 3 mph.

Other button is VSC or Vehicle Stability Control and includes TRAC or Traction Control. Stability control helps your vehicle maintain traction and control by reducing—or completely cutting—power sent to your wheels. It does this by automatically applying brake pressure on up to three wheels. The purpose of the system is to keep your vehicle headed where your wheels are pointed.

For Tacomas to pull things out or get unstuck without a rear e-locker (all but Off-Road models) that's why you will need to turn off the VSC/TRAC system or if a wheel spins power is cut to the throttle and ABS may be firing off so you will feel no pulling power. Same for Off-Road models in 4 Hi or not in 4 Lo with the locker on.

 

Alright, thanks for the detailed response. You've all been super helpful. My differential definitely does not look like that, so I don't have the e locker. Also I don't have any buttons in between the cigarette lighters. There are a total of four wires not plugged into anything. I have a green one where your rr diff lock is, and three on the lower set next to the mirror adjustment.

I jacked it up again just to make sure I was seeing things correctly. Both wheels definitely rotate in the same direction when I rotate one.