Does your speedometer get fixed when you change gear ratio on your truck?

2.7 5 spd 2.7 non-prerunner 2wd has a 3.307

2.7 auto non-prerunner 2wd has a 3.58

4.0 6spd non-prerunner 2wd has a 3.15

Prerunners & 4x4s were 4.10 in the 4 cyl versions and 3.727 in the 4.0 versions.

If you're feeling the urge to regear, selecting an OE option should make it easier, as you might find either a used gearset from someone who went bigger, or maybe a whole axle setup in a wrecking yard. (making the swap much easier for DIY)

 

Err... I thought the 4.0 V6 auto were all 3.73 gears (2005-2015).

 

What? 3.727 too accurate for you? I'll round up. 3.73.

 

You said prerunners. I was trying to include 4x4s too.

 

Correct. I edited to specify that. The outlier is the base 4.0 6spd. X Runner maybe?

 

I swear I thought my 6 speed came with 3.73's.

 

4x4 like your profile shows? It did.

The outlier is a non prerunner 2wd 4.0 6speed.

 

I'm trying to picture what model truck that is. Lower base model?

 

Thinking X Runner. 18" 5 lug wheels, ground effects etc.

 

You may be a little wrong. Mine is a 2.7 5 speed non-prerunner 2wd and has a 3.15 ratio

 

Is that like being a little pregnant?

Yeah, I know you said that before. Don't know where you got your info? I'm just quoting a spec sheet from Toyota, for Tacomas, that listed the gen 2 models.

You can argue with them. I really don't care, because I know my 3.58 is correct.

You could actually physically check it with little effort. http://www.how-to-build-hotrods.com/gear-ratio.html

 

Well I checked my VIN plate and it has a code were it says your gear ratio and mine says A05A. According to this table that's what it says.

http://www.off-road.com/trucks-4x4/tech/toyota-differential-identification-18588.html

A= 7.5" (diameter of ring gear)
05 = 3.15 (ratio)
A= 2 pinion

Idk, i may be wrong and that table too but i trust what it says in my VIN plate. But you may be right too. I guess i'll have to physically check. I just wanted to give you a heads up

 

Article you cite was written in 2000. Meaning at best it may have accuracy for 1st gen and back. When he uses terms like '86 to date, he means '86 to 2000 (date written), not 'now'.

Isn't yours an '06 as your profile indicates?

The PDF below was published in '13, but AFAIK all Gen2s played by the same 'rules' of drive line combos.

Still would be a good idea to physically verify yours before making any gearing decisions.

 

Oh thanks for sharing that man. I didn't notice that it was written in 2000 haha i'm an idiot!!

 

I threw my speedometer off swapping rear ends and tires on my 65 Galaxie 500. There is a formula they use to correct the speedometer on those cars. Mine had the C4 transmission. To correct the speedometer you had to change the speedometer cable gear which was easy (1 bolt and a clip). They take the tire height x the rear end gear ratio x the number of teeth in the speedometer gear to adjust the speedometer. On the old Fords it was just figuring out the gear with the correct number of teeth to correct this. The C4 had 4 or 5 different possibilities. I dont know if Toyota is similar or not.

 

Old school cars had gears in the speedometer cables that could be changed. On newer vehicles you can change settings in the onboard computer. At the end of the day they are simply counting wheel revolutions and doing math with a known tire circumference. Change the tire size and the math no longer works unless you compensate for it.

My dad worked in the shop at a Ford dealership back in the late 40's. They sold a new car to the local Sheriff as a patrol car. He brought it back complaining it wasn't fast enough. They tuned it and did everything possible but he still wasn't satisfied. When he returned it a 2nd time they changed the gears in the speedometer cable to make the car read faster than it actually was. That made him happy.

But either method only works with factory tire sizes. If a vehicle has the option of multiple factory sizes and you're truck came with the smaller size they can reprogram it up to the bigger size. Once you get to really big sizes you're off the charts and it is harder to calibrate.

But frankly this is something not worth worrying about. AT MOST you're talking about the speedometer being off by 5-6 mph at 70. In other words, if your speedometer says 64 or 65 you're doing 70. If it registers 70, you're doing 75-76. At slower speeds the difference is much less. At 55 mph you'd only be off 2-3 mph. This ain't hard to compensate for and no one is going to get into trouble within 5 mph at 70 or 2-3 mph at 55.

And this would be if you went 4-5" larger than stock tires. If you only go up 2-3" larger than stock tires the difference is pretty much negligible.

Another factor many don't consider is that even with factory tires your tires are constantly changing size. They get smaller as you drive. By the time you wear out a set of tires they are at least one size smaller than when new and you're speedometer will change by 2-3 mph. It is impossible for your speedometer, or odometer to always be 100% accurate since tire size is constantly changing.

 

an hour meter in conjunction with an odometer would be nice.