Nitro 4.88 Gear Install Question

All, has anyone here install 4.88 Nitro Gears on their 3rd Hen Tundra and had to also tune/change their gear ratio via tuner/remapping their ECU? I was told by my local gear shop that I will need to remap my ecu once they install my 4.88 gears because the truck will not shift properly, etc. Is this correct? Also, I have the Bully Dog BDX and I searched everywhere possible for the option to remap my gear ratios, but, could not find any way to do so. I need your help! Thanks.

 

Good question. I will be following this as I too want to install the 4.88 gears.

 

Hmm, haven't heard that one. I have 4.88 gears, and while I do have DAP tune, it doesn't do anything to the ECU as far as the gear ratio. I haven't had any issues with shifting. Your speedometer will likely be off by a few MPH after regearing, though. The only way I am aware of addressing the speedo is via a Hypertech speedometer calibrator. Fairly easy to do.

 

I'll call BS on that! Mine have been in since Feb of this year. My speedo has always been off because of the 35s. The speedo has not changed because of my gears.
If anything the transmission is now shifting when it is supposed to and holding gears like it is supposed to.

 

Ok, great information. Thanks.

 

That’s what I thought. It’s surprising that he would say that, given the fact that he specializes in differentials and transmissions, and do a lot of the gear upgrades. I’m glad to hear that the Tundras work well with the gear upgrades and do not require anything more in that regards. Thanks.

 

@Roman Do you have any experience in this area, and what are your thoughts? Thanks.

 

I have the Hypertech and bully dog and will be be installing 4.88s in the near future. I belive that with the 4.88s it should put my rig back to near stock gearing with the 35s , so i belive i could remove the Hypertech after 4.88 install.

 

Interesting. So, you’re running to different programs on your truck at the same time? I wondered how that would work. Thanks.

 

You can’t tune the ecu to know about a gear ratio change. Even using a Hypertech speedometer calibrator won’t make the ecu see the new gear ratio.

This fact doesn’t hurt your or the truck btw. It actually helps. The truck is seeing what it calculates as less load and adds timing and pulls fuel. These two things are the biggest way to make Hp

 

No sir, we haven't installed gears into a Tundra here.

 

I see. He actually showed me a big F350 that he installed Dana 90 gears and he used a tuner to calibrate the ecu or something like that.....to let it know the new gear ratios he said. Maybe this is something required for Fords and other makes, but not required for the Tundras. Thanks.

 

Ok, thanks Roman.

 

My 2000 F150 was the same way. I think the speed sensor is in the rear diff area. Had it regeared to 4.56 and had the Edge Evolution programmer. This programmer could account for different gears and tire size. Matter of fact it kind of required a programmer because the speedo and tach would go bat shit crazy without it.

 

When I re-geared my Tundra, the tech that did it, did say it was a real pain. It took him 3 times to get the pre-load perfect, and the front differential on our trucks aren't that much easier. His words not mine.

 

I believe i asked keith on that B4, Speedo is working great.

 

This>>>>>>>

 

I love my 4.88 gears! I would also recommend doing the Auburn LSD if you are changing your gears. Since they already have the rear end apart it’s easier to do. Plus it’s bad ass to have both your rear tires engage together equally when you need it. If your truck isn’t brand new I would also buy the carrier bearing kit for the rear end at the same time. It’s good insurance to make sure everything is in new condition. You don’t want any weak links in the chain if you know what I mean.

Here’s the specs for the Auburn LSD:
Auburn rear differential
High performance differential limited slip
10 1/2 12bolt
Part number:
5420134
36 spline axial
Non synthetic oil
80-90 Weight oil with additive


For the re calibration you asked about. Here is what I used.
Hypertech speedometer calibration module or hypertech intercepter.

 

Ok, so that’s why the technician believed that the Tundra needed to be reprogrammed. Very useful information to know and I’ll pass it on to the tech. Thanks for the info bro!

 

Yup, that’s what my tech said about my Tundra. He had quoted me a full days worth of labor based on what his computer stated it would take. But, halfway through the first day he called me to let me know that it would actually take two days.

 

Remember the operative word is "think".

 

Mine was 2 days as well.
$1200 for labor and oil.

 

Good info here, ive been wanting bigger tires but I would rather get gears first, I hear different opinions that you only need gears when going to a 37' tire. Some say get gears at 35s, some say 33's, so many different views, but I guess anything bigger than stock size needs gears ha!.

 

Thanks for the great info. I got the LSD earlier today. My truck is only 9 months old with 13k miles.

 

Yup, that how much my will cost ($1275). It should be ready by tomorrow.

 

All the truck performance shops that I have spoken to, strongly recommended the gear upgrades. They said that it’s critical for lifted trucks , as well as, oversized tires. It’s a must have for towing and heavy add-ones as well.

 

I imagine with 33s" tires and 4.88s it would be a beast off the line.

 

I'm going to also do mine here soon since adding 295 70 18 Nitto Ridge grapplers I have noticed a difference

 

I've been quoted 1200 and 1300

 

BS to a point. Recalibrate your speedo and you're back in business. No need to tune anything else. I run 4.56 on a first gen, same principle. My truck "thinks" its revving low to be at such speed, if I correct the speed it will "think" everything is normal.