Speedo gear

Wouldn't I just need the gear prerunners have when they run the 265s from the factory? Pretty much the same size tire as a 31. It also looks like 31s came stock this year cause they're in my owner manual. Wouldn't there be a size for the 31 inch tires?

 

Looks like these are the gears offered for 2 wheel drives. The bottom gears are for 4x4s. I just don't know what I need haha

 

Well I went to the dealer and talked to the service manager. My trucks speedo gear under my vin came up as a 17:6. There were 2 more options. A 17:7, and an 18:6. I ordered both and we shall see what happens

 

dumb question, couldnt you just use an ultra gauge, etc to calibrate your speedo?

 

I was told they don't recalibrate, they will just show the speed on the scan guage. They only way to recalibrate is to get an electronic inline recalibration device that is labor intensive and expensive to install

 

in that case i will probably get in touch with you to see what you did in detail to get my speedo correct after i get my 3" lift and new wheels.

 

I have been searching for an answer for weeks. Seems there isn't really an easy fix for prerunners. The 4x4s are easy, nobody can give me an answer for the prerunners. I'm going to try these to gears and see if they fix it. If not I'll either live with the slower speedo(and transmission not shifting sooner, which affects gas mileage) or get a digital recalibrator and try to figure out how to splice it in. Seeing as how your prerunner is a 2nd gen you might have more luck at this then me

 

Please keep the thread updated. Im really knew to all of this since this is my first truck.

I didnt know that larger wheel and tires cause your transmission to shift differently?

 

Hey no prob, we all were new to something at one time or another. Basically what my truck is doing now is just shifting later. It shifts due to the speed it thinks the truck is goin. Let's take my overdrive for example. With the old tires(speedo dead on), it would shift to overdrive at 46mph. Now with the bigger tires, it shifts when the speedo says 46 still, but my actual speed is closer to 50. So basically it shifts late. This is not as much of a problem as shifting early, it just uses more gas.

 

That makes perfect sense.

 

Being serious or sarcastic lol? I have heard second gen tacomas are actually not accurate on the speedo from the factory. One tire size increase will put you dead on. So depending on how big you go will determine how far off it will be. Just don't forget that depending on how big you go, you may have to regear your diff. I got lucky and have a first gen which is actually geared for a 31" tire. And btw, congrats on your new tacoma! You selected the best midsize truck there is

 

I am being serious.

Sorry if it wasnt clear.

 

I don't think the trans shift point are dictated by the indicated speed.

The reason the trans shifts when it does is because of load, both transmission and engine. The reason it is shifting at the point it is, 50 mph now, is because the load is the same at that speed now as it used to be at 46 mph with the smaller tires. The larger tires make the engine and transmission work harder to reach the same load level. This is why many of us regear to a lower ratio to compensate.

This is true of 1st gens as well. When I was stock, mine was about 5% under. The speedo read 60 but actual was closer to 55. Many others on this forum have reported the same thing. When I increased my tire size from 31's to 32's, the actual speed matched the indicated, essentially eliminating the the 5% error.

 

My new wheels and tires don't weigh that much more then the old ones. I swapped from stock steelies to alloy rims with 31s which is supposedly what it was actually geared for with the 4.10 rear gearing. I've been doing research on this for awhile and everybody says that the tranny shifts from the indicated speeds from the VSS. I even found a thread where the speedo was reading real low and a guy was having trouble cuz it would shift early and then it would kick it back out the gear cuz the engine was lugging to hard

 

The computer takes a whole bunch of stuff into consideration when shifting. Rpm, vacuum pressure, temp, load, and speed

 

I still think that Nike or Spalding is every bit as good as Speedo.

 

I just upgraded from 31x10.50s to 255/85s (slightly larger than 33). My speedometer was reading slightly fast, however my odometer was about 6-7% slow. If I drove 20 miles it would read about .1 less than actual.

My truck is a 99 2.7L Auto TRD Prerunner with stock 4.56 gears. I pulled the speedometer gear out of the passenger rear side of the transmission and counted the teeth. It had 17 teeth. After reading other threads on here and TTORA I knew I needed a gear with one or two less teeth.

I came across this thread http://forum.ih8mud.com/threads/speedometer-correction-by-t-case-gear-change.480939/ talking about 4Runners. There is one gear with 16 teeth for a 2wd w/electronic sensor. I decided to take a chance and ordered one for about $15. When I received the gear I compared it to my stock one and it is almost identical in every way, even the shaft is the same. The only difference being the one less tooth.

I swapped this gear in (pt# 33482-39405) and now my odometer is dead on. The speedometer is back to being 2mph fast, which it has always been. When going 75 on my speedometer, my actual speed is 73 according to GPS.

I just wanted to share this information in case anyone with a 2wd needs to correct their speedometer. You can see by the pictures that the gears are identical in size.

 

Looks like the above part was replaced with part # 3348239900

 

I replaced the original 17-tooth gear set with the above 16-tooth gear set. It brought the mph closer to the actual mph as reported by my gps but still under. Anybody know if there is a 15-tooth gear set?

Example:
Speedo currently reads 55
GPS currently reads 57