2008 Tacoma V6 Overdrive RPM Problem?

Hi I have a 2008 Tacoma v6 4x4. From what I noticed the transmission works well and shifts find in all gears, including overdrive. But after watching some videos on the same 2nd gen tacomas on the highway I noticed they all rev lower than me at highway speeds. Mine is an auto and I do understand that the manual revs higher because it’s 4.10. But the trucks I’ve seen are the same as mine (auto trans) and they seem to rev lower. For example my truck at 60 mph revs about 1700-1800 rpm. While others rev only about 1500 at the same speed. I’ve attached two images. The one That is reving slightly higher is my truck (between the 1500 and 2000 mark). The other photo is another truck that is reving only 1500 rpm at 60. Both trucks are going 60 mph. Is there a problem with my truck? It did this same rpm with my stock tires and bigger tires. Please help. Thanks

 

Do you have a v6 or a 4 cyl?
Also keep in mind it depends on what tire size the people are on. That will affect mph vs rpm. If you have a 4 cyl they come with 4.10 gears, v6 autos come with 3.73.

 

Check your manufacturer code on the door jam for diff ratio. I wondered the same thing since mine spins at 3000 rpm going 80 mph. 4.56 in off road diffs

 

My truck is 3.73 gears. The other truck is also v6 and 3.73. If anyone has a 2nd gen auto v6 tell me the Roma your truck is at 60 mph. My truck is v6.

 

Hopefully I’m not adding to any confusion but:

2007 Double cab short bed TRD Off road 4x4 4.0L V6

Running 315/75r16, wheel and tire combo weigh 90lbs a each. Not stock size but every little bit helps right?



*Speedometer (GPS Speed) - RPM*


Just a random thought, have you disconnected the battery to reset the computer lately? The trucks do learn how you drive, to a certain minimal point. It’s not anything drastic but it’s free.

 

I will try and reset my computer. So the gps is your true speed right? I’m only running 265/75r 16s. They are heavy at 75 pounds each because they are 10 ply. But I felt the rpms were the same at 60 even with my stock 245/75r 16s.

 

Correct, gps is true speed.

 

Mine is the same. Just over 2,000 rpm @ 70

 

I guess I might be overthinking this. Maybe nothing is wrong. Just thought the torque converter isn’t fully locking up in over drive.

 

The first pic you posted honestly isn't that bad I feel.

Were you on flat road (no hills), any wind blowing with or against you in either pic?

I don’t think I would worry too much.

 

Nope I was actually going downhill to see how lowthe RPMs would go to.

 

I’m shocked that the speedometer is so off.

 

1st pic looks like you need to put air in them tires

 

The tire pressure gauge is always on. The first owner didn’t replace them when removing the stock steel wheels with the alloys.

 

Almost a 35” tire vs the stock 265/70r16. I’ll eventually get one of those boxes wired to fix it, for now I just drive 5 under speedometer everywhere I go lol

 

With larger tires I feel like the speedometer would be higher than the GPS speed.. truck thinking it was going 70 but in reality it’s going slower because of the bigger tires.

Obviously my train of thought is wrong and I’m sure there’s a reason why lol

 

Won't help. Won't hurt anything, but it's unrelated.

No. Your taller tire reduces the effective final gearing by ~3.9%. But your speedo is wrong by that amount. So reading 60 you are doing 62.33.

Yes. I'd wager there's nothing wrong with your trans. At least related to this.

These tachs are not precision instruments, just like the speedos aren't. Comparing to another vehicle is an ok rough estimate, but how do you know it's not the one that's (more) inaccurate?

A great way to check is to plug in a real time OBD2 reader and see what the actual RPM is while using the GPS for MPH.

Many people claim 'OCD' about such matters. Hypertech makes a corrective device if you really want the speedo adjusted.

 

So I am using this calculator here:
http://www.grimmjeeper.com/gears.html

1.Select Toyota A750 (E/f, doesn't matter)
2.Toyota Tacoma & FJ
3. None
4. 3.73 gear
5. 265/65r17 (Stock trd sport tire size)

Next I input 60 MPH in the last table,
In 5th gear you should be at 1772 RPM at 60 MPH actual. On a stock ODO w/ stock tire size your ODO is off by about 2 mph at 60. So 60 on odo is about 58noh actual.
At 58 MPH in the calculator it says RPM should be 1713 in 5th gear.

Your truck appears to be in spec, so the people running at 1500 may have oversized tires which is bringing their rpm down at the same speed.

 

I appreciate the help. I’m thinking my truck is fine. Thanks for the help and research. Love this website.

 

I hear ya, I had 305s last and it took me 3 of the 5 years I had them to wrap my head around the whole idea.

To add to my original post as well, I don’t know how much it affects this whole RPM thing overall, but I travel 13% further than I do on my odometer. Meaning, my odometer may read 221.7miles but I’ve actually traveled 250.5 miles.