It's extremly difficult to find Toyota Mechanical Specs

Finding 2022 or any year 3rd gen specs is murder. Toyota sucks at giving mechanical specs. Spent a week finding tranny gear ratios for the 6-spd manual. BTW that's how I ended up at TacomaWorld The people here are very smart and very generous to supply specs.

Now I am finding different answers for my differential axle code. It's a B07B. Many kind people have posted codes here & other places but they are honest people and warn that the code for 4.3 has not been verified

Jacking up a tire and rotating twice, is still not accurate enough to calculate. It's easy to determine 2 exact tire rotations but the drive shaft counting is difficult when the 2 ratios offered are so close, 3.9 vs 4.3.

The reason is it's a guess for that final drive shaft movement. You have to know almost exactly what fraction of a full turn the shaft stopped at

Now, every tire manufacturer has stated that a 265R70 has a circumference of 8 feet. You could use this to calculate rear axle ratio

MPH = (Engine RPM x Tire Circumference x 60) / (Tranny gear ratio x Differential ratio x 5280) BUT we don't have that accurate enough speedometer. The 5280 converts Feet to miles and of course the 60 coverts Minutes to Hours

Do the algebra and we get
Differential Ratio = (Engine RPM x Tire Circumference x 60) / (Tranny Gear Ratio x 5280 x MPH)

Example MPH = 25
Engine RPM = 2500
2nd Gear ratio = 2.017 ~= 2.0
Tire Circumference = 8'

Results in Diff Ratio = 4.3

BUT..You need a very accurate Tach & speedometer to distinguish between 4.3 and 3.9

These electronic tachs and speedos are not all that accurate enough to "split hairs"

My Axle code is B07B supposedly the "07" indicates a 4.3 axle ratio PLEASE Help?

Also where can I find a torque curve for the 2002 6 cylinder engine

 

Edit:

My supplied info was based around Gen 1 trucks, I see you're asking about multiple generations here now and I'm not experienced enough with the 3rd gens to tell you gear ratios of my head.

The 2002 3.4 has a torque curve?
(Peak HP/TQ is around 4500rpm IIRC)

Never heard of a factory 3:90 gear ratio.

Factory ratios are:

Manuals w/ V6 4:10
Autos w/ V6 4:30
All 4Cyls 4:30
Optional but very rare 4:56 had to be ordered this way.

There are of course some outliers and if you're not the original owner something may have changed like myself below:


I would bet dollar to doughnuts you have a 4:30 rear end just on statistical probability and your own math.

Doing the tire turn test is very accurate if you mark and watch the input flange and have someone else turn the tire.

That's how I determined my 2000 had a 4:10 (V6 manual) and how I determined my E-Locker diff from a V6 auto was 4:30 when I swapped it in.

The only other factory gear ratio I know if is 3:73 for 2nd gens.

 

I hear ya on finding some of Toyotas specs. If the trucks a 6-sp manual it is a 4.3 ratio. Toyota does have a table showing axle ratios based on truck configuration. Sorry can't help with the 1st gen question.

 

Welcome to the forum

2 axle ratios only for the 3ed gen:
3.90 for 6 cylinder automatics.
4.30 for 6 cylinder manuals and 4 cylinder automatics.
No manual 4 cylinders were offered after 2017.

Look here: https://www.tacomaworld.com/threads/axle-gear-ratios.724486/
Post #7 has a nice chart,

 

THANK YOU ALL!!!!! And GOD BLESS you ALL I never found a more friendly bulletin board

 

You haven't seen our best yet -- we like to help you !

TW motto: The most expensive one is the best one.

Seriously, many great folks here willing to help and share, lots of knowledge and resources.

 

Folks how do I reply directly to a person? Any way @Key-Rei Thank you, It was My mistake, I was quoting the ratio for the automatic tranny when I quoted the 3.9 in my first post

 

@RustyGreen THANKS!!!!!

 

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I'm nearly 70, This will be my last vehicle most likely. I'm actually a SUV type BUT as you all know Manuals are only available on Tacoma and Jeep. Of course they are also available on very expensive but totally useless cars in bad weather such as Porsche etc.

I LOVE doing math and deriving things for myself, I have been told by 3 Doctors, doing puzzles or in my case math actually is a good preventative for senility. I am NOT joking it's a fact.

My BEST car was a 1985 Isuzu Trooper. Turbo 4cyl DIESEL (Tons of low end Torque) It's MANUAL transfer case had not only 4H & 4L BUT also had 2H & 2L. It also had auto locking hubs, all you had to do was travel about 6 feet in reverse in either 2H or 2L to unlock them. It had a 5 spd manual and NO DAMN ELECTRONIC ANYTHING!! The transfer case was also "stick" operated

It took me three days to master the "Tall" 1st and Reverse on my new Tacoma. I HATE slipping clutches and also driving a 10 wheel garbage truck (back in my college day summers) SPOILED me rotten.

it was a 2 stick Mack duplex tranny. 5 speeds on one stick L & D ( D was 1:1) on the other. To get her movin you used L-2 and just let the clutch out gently. When loaded you used L & D to split each gear hence a 10 speed tranny

And using Reverse-L made backing up to large containers (Dumpsters) EASY as PIE

I LOVED it you shifted like this 2L then 2H Then using BOTH hands one stick to L the other to 3rd then the one stay in 3rd and shift to D NO Clutch either you learned to drop revs by ear.

Again THANK YOU ALL for the information, it's much appreciated!!!!!!!!!!!!!!!

 

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@TnShooter
How do you add the arrows?

 

I had to take a screen shot, then add the arrows myself in photo editor.
(I have an Apple phone, it has the feature but into the photo editor)

 

Hi Key-Rei thanks for the response. Yep, I thought about it & came up with a super accurate technique. As you said have a friend help and paint mark on the flange or drive shaft. Turn the tire NOT 2 full turns BUT Six or Eight full turns.

Then divide # of Drive Shaft Turns by either 3 or 4 (3 for 6 tire turns, 4 for eight). Doing more tire turns eventually has the decimal part of the diff ratio add up to at least 1 full turn of the shaft

BTW I did some fiddling with that equation and BINGO Speedo was reading 60 MPH and Tach was dead on 2000 RPM in 6th gear (0.713:1) Exactly what we would expect based on tire manufacturer quoting 8' as effective circumference

Thanks again for all you input & information BTW I screwed up BIG TIME when I gave my equation. Though it is correct, I FORGOT to Reduce fractions 60 / 5280 reduces to 1 / 88 LOL

Hence:
Speed MPH = (Engine_RPM x Tire_Circumference) / TransGearRatio x DiffRatio x 88


Rearranging by dividing both sides by speed and multiplying both sides by Diff Ratio we get:

DiffRatio = (Engine_RPM x Tire_Circumference ) / (TransGear_Ratio x Speed MPH x 88)

 

This is all true but there's no reason you must only rotate the tire twice. If you run into this again, rotate the tire 20 times while your partner counts driveshaft revs and then divide driveshaft revs by 10. You'll know the difference between 39 driveshaft revolutions and 43 revolutions. The more rotations you use, the smaller your error.

 

I don’t see gear ratios on this document, but you may find some other interesting Specs.

http://www.tfltruck.com/wp-content/uploads/2015/08/2016-toyota-Tacoma-Technical-specs.pdf

 

Brilliant. I love stuff like this. Makes complete sense, but often overlooked. Good shit dude

 

Were you born without eyelids?

 

Yeah, assuming that you don't lose count around your 14th time rotating the tire

 

That’s easy. Just count how many the other side spins and divide by 2. Then count 21.5 on the drive shaft.