4.56 or 4.88? Or...?

Im looking to regear my truck, but I need some serious help deciding which gearing to choose. I dont have a big problem with the shifting anymore, atleast IDC about it anymore, but I do have 2
1. Getting some power to pass on the highway without having to shift down to even 3rd at times.
2. Maintaining 80-85MPH without shifting all the damn time. As of now it can be a relatively flat piece of road and my truck will still pull off all sorts of shifting when trying to maintain 80mph.

Does anyone have experience using either of these two gear ratios on "33s." I have 265/75r16 tires, might go "true" 33s later. I just dont want to be running 3000 rpms trying to do 70mph on the highway.

Also, where could I find 4.56? I havent had that much luck finding some for the e locker diff.

Someone had linked me to a chart that shows what rpm I would run at what speed for different tire/gear combos. If someone could link me to it I would really appreciate it.

 

By what the chart says, if im gonna be running 3367rpms at 65 then Ill be running close to 5000rpms at 80mph

 

I don't know how accurate these charts are.

I am running 285/75/16 with the stock 3.73 gear ratio. This chart says I should be at almost 2500 @ 65.
Driving home on the freeway I was more around 2000 rpms @ 65.

 

It depends on what it is using as the gear ratio, since all the transmissions have different ratios. I'm not going to check, but it could be assuming a 1:1 trans gear ratio. That would simplify the math and make it comparable across all transmissions, since I think all the transmissions used in our trucks have a 1:1 ratio.

 

Looks like Fifth Gear ratio on a 2013 Tacoma 4x4 Auto is 0.72:1 at the transmission?



Honestly I don't know the math but I think I will look it up today.

 

Check this out, itll be much more accurate once you select your trans or enter the ratios

http://www.grimmjeeper.com/gears.html

 

The math isn't hard, you just have to get the units to cancel out until you get MPH. Gear ratios are calculated as input/output, so ...

RPM x (1/Trans Gear) x (1/Diff Gear) x Tire Diameter (in inches) x 0.002975 = MPH

or

MPH x Trans Gear x Diff Gear x (1 / Tire Diameter (in inches)) x 336.135240 = RPM

 

Very cool site and easy enough to fill out.

Ignore the fact that I added a crawl box to the config. It doesn't impact the highway driving section.

Basically this is a 4.0 V6 with factory 3.73 gears in the rear compared to 4.88 gears running on 285/75/R16 tires.

The very last chart is the one @Wixo is probably most interested in. It shows RPMs at 3 given speeds.

 

Agreed, very user friendly and lots of valuable info for comparisons

 

The sticke ron my door says A/TM: B07B/AC60F Which one do I choose? The closest I found was Toyota AB60F

 

I don't know the tranmission model in the 3rd gens but i found this and you can punch the numbers in manually.

Found this here https://www.iseecars.com/car/2017-toyota-tacoma-specs

 

The numbers also match up with the numbers on marlincrawlers site.

https://www.marlincrawler.com/tech/transmission/transmission-gear-ratio-chart

 

Awesome thank you!

 

Thank you too!

 

@Wixo and I think your diff gears are 3.91

 

What am I doing wrong now?

 

Ok I realized I left forward gears as 1. Fixed it and Im seeing that at 80, with 4.88s, Im gonna be running 2540 rpms, which really sucks for economy. Im better off with OVTune GearLock and leaving it in 5th.

 

Usually you regear because you went up in tire size and you want power back.

Regearing won't fix the transmission software problem that seems inherent in the 3rd gens.

If you regear and keep the stock tire size then yes your RPMs will be higher and fuel economy goes down.

Somewhere our numbers are off as I am seeing 2540 rpms @ 80.

Below I am using 255/85/16 which is skinner than 285/75/16 but more of a tru 33inch tire.

 

Try putting in 4.88 on the left side. If I got 2300rpms I'd be ok, but no worries Ill just drive faster to maintain gear lol.