35" Tires, 4.88 Nitro Re-Gear and a Hypertech Inline Speedo Calibrator

So you have 35" tires, Nitro 4.88 gears, and a Hypertech plugged in with wheel size correction only?

 

Yes. The Tacoma uses the ABS sensors to calculate speed, thus only tire size and pressure will affect the speedometer reading. An argument could be made for adjusting the transmission shift points based on driveshaft speed when you change gears, but the hypertech can't do anything about that.

 

You answered your own question.

The hypertech has nothing to do with your issues.

Whoever installed your gears F'd something up.

I have 33's, the Hypertech and 4.30's...no lights, no issues. The only thing I programmed in the Hypertech was the new tire size and it's spot on.

 

Are you sure that your front and rear gears are the same?

 

I would verify your gear size. Jack up all tires, put into N and count wheel revolution vs axle revolutions in the front vs the rear.

 

I didn't count the teeth on the two sets of Ring/Pinions when I received them, or do anything other than sign for the delivery, put them in the bed of my truck and drive them down to the shop. Not meant to be cynical, at all - good question. I bought the gears from a 'group buy' on this forum, signed for the delivery when they finally came off backorder, and brought them to the shop to do the install.

Part numbers on Nitro boxes: Front: "T8S-488R-NG" Rear: "T8.75-488-NG" Image Attached.

 

If the gears were mismatched front to rear then that truck would buck and bind like a SOB

 

Wouldn't it only buck if he got it into 4wd? I believe the sensors are reading two different speeds and not allowing the 4wd to engage therefore keep flashing with warnings.

 

Interesting thought. Would that kick out an error code, if sensors are reading 2 different speeds?

 

I'm not sure where you would even look a code like that. That would be the next thing I would check after all the sensors have been checked. Do you still have the boxes they were shipped in?

 

FWIW - I just sent an email to the folks at SDHQ in Arizona, with a picture of the gears - asking them to confirm at least the labels indicate the right gears were purchased and supplied for the install. I'm going to assume (consciously) the gears from Nitro in the box matched the labels on the boxes.

 

I think it's a wire/sensor damaged somewhere. Many people have ran the combo 35+gears+hypertech with no issues

 

At this point, I would welcome a damaged wire/sensor and replacement as a solution. When the shop hooked up a scanner, it did provide an error code for a mis-read front right sensor, which they replaced last Friday. After replacement, the scanner did not pickup any other error codes. Guess we'll find out again today, given the lights are on and seems like there's a code just waiting to be read!

 

Did they actually replace the sensor or just reset the code to get you to go away?

 

Said they replaced it.

 

Does the 4x4 light flash like it wants to engage but does not go into 4x4 or does nothing happen at all. It would make sense that if the truck can not read the wheel speed at all 4 corners it would not engage 4x4 because it does not want to damage itself.

 

The green light does not flash. I immediately get a graphic saying "2WD-4WD Mode Change Failure". Pic attached.

 

I'm going to say this is a damaged wire or sensor, and I am not sure how exactly the sensors read the wheel speed but there could also be a damaged pick up for the sensor. If the gears were wrong the truck would bind when it would finally go into gear. Depending on how close the ratio would be would determine how much bind, but you would notice it. Since it does noting for you it comes across as a fail safe in the truck.

 

Juts spoke to Gary at Hypertech Technical and he confirmed that the Inline Speedo Calibration for the Tacoma does not use the gear data, only the wheel info. Also, to measure the wheel size to be sure its acurate - 35" Nitto Ridge Graps are actually closer to 34.25" - for anyone interested. This difference in actual wheel diameter cannot be any more than 10% off or it will kick off ABS lights. Now, I originally had entered 35" - so 34.25" is a minor correction there. Nonetheless, I reprogrammed the unit to say 31" old diameter & 34.25" new. Not sure that will make a difference - will update when I know more.

Incidentally, the stock 265/65 r 17's... are those indeed 31" in diameter? I'm also reading 30.6" Not that it will make that much difference ... but at this point I'm not assuming - want to be as precise as possible.

 

As long as all 4 tires are the same it should not turn abs light on. What hypertech means is you can not have a 10% difference in the tires on the truck. As in you can't run your factory tires on the front and 35s on the rear. There are plenty of people running 35s without the computer re calibrated.