Speedometer Drive Gears

Hey, Guys.
I just regeared the tundra with 4.88's and my speedo is off. I know the tacomas have a speedometer drive gears that you can change to correct the speedo. Do our first gens have a speedometer gear? If so, where can I buy the new gear? What part number?

Thanks

 

I've not seen such for our trucks, some of us have gone the electronic route with success. Yours being an 06 might not be as easy, but take a read through here for details.

https://www.tundras.com/threads/yellow-box-speedo-calibrator.31996/

 

YellowBox, yeah, I've seen that but that looks like a pain in the ass. Do the Tundra's have a sensor in the trans (speedometer sensor)? The sensor has a gear that you can change out to help with the increase tire size and MPH.
I want to change this gear but don't know what gear to get. Just curious if anyone has done this before. Still searching the web...

Here's an article for the tacoma. Curious if it's this simple.

https://adventuretaco.com/replacing-the-speedo-gear/

 

Yes, they do have a sensor, however if your truck is newer than 03 then it also takes speed signals from the ABS. If you were to change the gear or the sensor you'll have a speedo that doesn't work.

Read through that thread, its really your best bet. Looking over that thread, why settle for "different" speed when you can get accurate?

 

Still searching but it's looking bad. I went under my truck and looked at the tranny, I don't see anything resembling this sensor. Cross reference the part number but nothing for my 06. You 04 and older guys might want to look into this.

@Darkness Saw your post about the yellow box. I emailed them to see if it's going to work for my 06.

The problem I'm having is after I re-geared.

Before gears 3.91 with 34" tires - Speedo reads 70 but GPS reads 77 (2200- 2300 RPM)

After gears, 4.88 with 34" tires - Speedo reads 70 but GPS reads 77 (2550-2650 RPM)

This doesn't make sense to me. I should be closing the gap in my MPH with the new gears. I'm basing this theory off my Tacoma that I re-gears with 4.88's



https://www.ebay.com/itm/21-Teeth-T...edometer-for-Toyota-83181-35040-/222514424510


2004 Toyota Tundra Base Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2004 Toyota Tundra Limited Crew Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2004 Toyota Tundra Limited Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Crew Cab Pickup 4-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Crew Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Extended Cab Pickup 4-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2004 Toyota Tundra SR5 Standard Cab Pickup 2-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2003 Toyota Tundra Base Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2003 Toyota Tundra Limited Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2003 Toyota Tundra SR5 Extended Cab Pickup 4-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2003 Toyota Tundra SR5 Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2003 Toyota Tundra SR5 Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2003 Toyota Tundra SR5 Standard Cab Pickup 2-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2002 Toyota Tundra Base Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2002 Toyota Tundra Limited Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2002 Toyota Tundra SR5 Extended Cab Pickup 4-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2002 Toyota Tundra SR5 Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2002 Toyota Tundra SR5 Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2002 Toyota Tundra SR5 Standard Cab Pickup 2-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2001 Toyota Tundra Base Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2001 Toyota Tundra Limited Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2001 Toyota Tundra SR5 Extended Cab Pickup 4-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2001 Toyota Tundra SR5 Extended Cab Pickup 4-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated
2001 Toyota Tundra SR5 Standard Cab Pickup 2-Door 3.4L 3378CC V6 GAS DOHC Naturally Aspirated
2001 Toyota Tundra SR5 Standard Cab Pickup 2-Door 4.7L 4663CC 285Cu. In. V8 GAS DOHC Naturally Aspirated

 

If your truck takes speed signals from the ABS then it does make sense. Your change in tire size would be detected but the change in transmission speed would not be detected. Your motor and trans are spinning faster to reach 70 but your tires don't know the difference.

It seems the only option, if similar to the 04 in that thread, is to catch the signal wires and forget about the trans sensor. Not as easy as you'd like but from what you said the gear won't do a thing.

03 and earlier (04 is hit or miss) don't take speed from the wheel sensors at all. My 03 with stock gears and 33s would read 9% slower than actual speed. I added 4.56 gears and suddenly I was 8% faster than actual speed.

For those older trucks the plug and play works perfectly, install takes less than 20 minutes and calibration depends if instructions are read or not(I didnt read). I've installed two of those and the calibration was about 30 minutes of driving.

 

On 32.8” (285/75/r16) tires with 3.91 original gears here. I calculate an 8% difference based on some ratios online and what others here have said. Speedo reads 65 when actual speed per radar is 60ish.

I wonder if that little gear mod (in the above link) would work to bring my 2002 Speedo back into parity?

 

Opps! Speedo reads 65 and actual radar is 72.

 

I was thinking that my sensors in the are either confused and don't know what to read OR that I went to tall of a gear. I called Justdifferentials.com and Al said that with 35's I need 4.88's but since you mention it, it makes a little sense about my sensors.

I waiting to hear back from yellow box and I'm hoping, since its 2020, they'll have a better solution. I wish someone would just come out with an OBDll module like all the new trucks so we can calibrate. Its 2020 for crying out loud!

 

A lot of 1st gen Tacoma guys are doing this. That's why I was pondering and looking for something similar. Since I have an 06, I don't have that option.

 

4.88s is a good ratio for running 34 or 35s. It's better to gear a little over.

A gear calculator will tell you 4.56 matches 35s and 4.30 matches 33s. What they don't tell you is the extra weight of the tire makes a difference, they only account for height. That's why I went 4.56 for 33s and if I went any bigger I'd go 4.88s. Just Differentials is a great shop, I talked to them before I regeared too.

These Toyota ECU are not easy to mess with, I don't see an OBD plug option in our future unfortunately.

 

Yeah, they have great customer service. I plan on towing a travel trailer and my Tacoma, so 4.88's are good. I just wish someone would come out with something. I'll let you know what I hear from yellowbox. Hopefully they figured something out.

 

use a Speedo calibrator from yellr.com. tell them you want 2.5 meters of wiring harness and you'll be good to go.

 

Already emailed them and according to @Darkness and other forms, anything from 05 and 06 yellowbox doesn't seem to work. Waiting to hear back from yellowbox about my 06. Stand by.

 

Well that's sad if they don't. I was planning on using them to save the day for me when I went to 35s and regeared.

 

Why have I not heard about this little gear mod for the 00-02 1st Gen Tundras before?

 

Well it's not really advertised towards us first gen crowd. It's a land cruiser thing im pretty sure. But the powertrains are close enough that someone eventually asked why not.

 

Someone stop my desire for experimentation and going where no man has gone before. Will this work guys? The Taco people reviews look good. Their 1st Gen Taco has same A340 transmission and transfer case as the 2002 Tundra A340F?

 

Go where no man has gone before... You're the chosen one.

Check out this link. https://adventuretaco.com/replacing-the-speedo-gear/

 

I’ll go there boldly. Live Long and Prosper.

 

If anyone can do it golden hands can.

 

I’m having another Flat Earth Society moment on this little pink gear. I think it will work opposite of my needs as I’ve never regeared and just have the bigger tires (285/75/r16). My paradigm is rocked right now and might suffer from insomnia over all this tonight.

 

Well this whole thread is news to me because I didn't know 06 was so different with the sensors. I'm about to buy tundra no.2 for me and I want a first gen so I'm buying an 06 dc big enough to comfortably haul the whole family. It is tight fitting 3 kids across the back of my ac. But I'm keeping it for sentimental reasons. Owned it for 17 years. Was a gift for parents and grandparents. But my new 06 is planning to get 3-4 inches of lift and some 35s and lockers and regear to somewhere in the 4s and I desperately want my Speedo to work right. I've been under the impression that the yellow box would solve all my problems.

 

That's what I did. Got an OEM style 3" coil over, a true-trac and 34's. After re-gearing, I spoke with www.justdifferentials.com and told them my situation. In a nutshell, he said that my RPM's are dead on but it sounds like my sensors are confused.
When I had my 3.91's and with my 34's, traveling at 70 I was really going 77 (GPS). Nothing changed when I went to 4.88's except my RPM's. The MPH stayed the same but the RPM's went up. My MPH should have closed that window but it didn't. My 2004 Tacoma closed that window when I re-geared.