What are potential issues by re-gearing a Gen 3 to 4.88?

Im about to add a 3 inch icon lift and put 33's on my 2021 Tacoma. Ive read about all the great things re-gearing to a 4.88 will do for even a stock Tacoma especially with the lift and tires I am about to get. I want to re gear mine soon yet I am hesitant because I never read anything bad about re-gearing. Its tough for me to re gear a brand new truck. If you could please answer a few questions I have. If I do re-gear, it will be done through a recommend 4x4 shop that does put a 30,000 mile warranty on the work they do. They do them often.

What are potential reasons to not re-gear, technical problems it will cause?

Does the re gear cause future damage that I don't know about?

Is it safe to do to my daily driver vehicle?

Warranty issues?

Lastly, if you have re-geared, what questions do you wish you would have asked or known about prior to re-gearing?

Thanks for any info you can provide.

 

When you regear, your driveline warranty of 5yr 60K basically goes away. If you would have any transfer case or transmission or anything in your driveline, Toyota has a valid reason to deny warranty. Before the guys who will come in screaming Magnuson Moss, remember Toyota has nothing to prove... they can deny and it's up to the customer to prove otherwise.
Not saying they will it just gives them a very valid reason if they so choose. Otherwise I can think of nothing else.

 

You'd like it too much. You'd wish you'd done 5.29 gear instead.

 

Done right, no down side to it.

 

All the fly honeys that you'll have to shoo off constantly

 

Would 5.29 be too much for only having 33's?

 

Would re-gearing actually cause any of this or would this be if something randomly does happen... knocking on wood... I feel like Tacoma's are tanks and I shouldn't have a need to pull a driveline warranty.

 

If something bad DOES happen, less likely to be a cause. Although I imagine if you have a transmission issue the dealer is not likely to pull your diffs apart and see if you’re regeared. Just don’t mention it.

One possible downside, you may get some howl from the new gears. I did when they first went in but it went away after break in and can’t really be noticed now.

 

Presuming you are AT - Before you re-gear I'd suggest you consider OVTune to fix the drunk monkey shifting. Find someone in your area to do the flash for you (unless they charge more that the cost of the hardware/software) and see how you like it. The Tune can be specific to tire size and gearing. I re-geared to 4.88 long ago on my DD - some go to 5.29's - both are way better than the stock 3.90. I'd do it over again (re-gear) hands down. Between -re-gearing and OVT you will be amazed at how well the truck performs.

Side note - if you add your general location to your "personal details" it may help others steer you to a good shop or a person who does the Tune. GL.

 

Build your rig as you would like it. The less it’s in the dealership being jerked on the better. Get to know this 4x4 shop. Ask these questions of them too. What’s just as important as a great truck is an equally great mechanic that knows what their doing. Ive always been reminded how great my factory warranty was but then had crap techs that didn’t know what they were doing and made things worse. Warranty doesn’t last forever so just build it and live.

I was on the path to have my diffs regeared with my sport before it was written off and what I was going to do was install a locker as well. If you live where there is snow 1/3 of the year and ever tug vehicles out of ditches or maybe throw in some off-roading once in awhile too, a locker is just good to have.

 

Probably not, but there are lemons on even the best vehicles. Even putting 33's on there is enough for them to use it to deny warranty if they want.
For an OEM, they fully expect to warranty what they build.... this means how it was delivered to the dealer... which means stock.
You really can't expect them to warranty something they did not do right?
In my world if any of our customers modify our components or system there is zero warranty and it's spelled out.
Again, this is the only downside. Do it or not, just be prepared of the possibility.

 

No down sides to regearing to 4.88 gears. But if your thinking about adding a bunch of weight (armor, winch, canopy, RTT, etc) or tow much then you might want to consider 5.29 gears. And if you think you would ever want to add a front locker, now would be the time to do that.

 

That was going to be my next question, how would they even know that I re-geared it, unless I told them I don't think they are going to look for it. what did you re gear to? Do you wish you did a different gear or are you happy with the one you picked?

 

Thanks for this note, ill add my location to this. I am up in Fort Collins, Co.

Do you wish you would have gone with 5.29's over the 4.88's?

 

Curious, my interpretation is that only burden the consumer has is that they bought a consumer product and the warrantor is offers a clear warranty for which the product meets requirement. My understanding is warrantor is required to prove aftermarket parts caused the failure, e.g. aftermarket wiper blades caused wiper motor to fail. It is on the warrantor to prove that. And used that particular argument with Toyota and won. Not a wiper motor but same idea. Toyota could not prove that my part caused another part to fail.

*edit... that said when i regeared and grenaded the rear end, it obviously wasn't toyota's fault and the rest of the driveline was unharmed.

 

Definitely my thoughts as well. I wouldn't attempt to call them on a warranty issue after I modded something which is why I'm attempting to see if its worth the gamble for me.

Thanks for the input!

 

Imo it may only affect the warranty (if applicable). I can't statistically fact check this but I'm sure not regearing may lead to issues if you are running larger tires and added weight, same goes for the opposite (regearing on stock taco).

 

I am south of Denver and did 4.88 about 18 months ago. Best thing I have done for the truck especially living at 6050 ft above sea level and driving over the passes loaded with people and camping gear. These trucks are not the fasted things to begin with and border on being over-geared from the factory. Start adding weight, bigger, heavier tires, more drag, and even less power due to elevation and it's not great. I did the OV tune first and that kept me happy for about a year but finally realized I needed to regear and should have done it sooner. With that being said, the truck is brand new. I would drive it stock for a bit and then see what you think

 

Not regearing is going to mean your truck is working harder to turn bigger wheels.

Gears are pretty simple, there isn't much they would affect unless installed improperly or they failed. I don't know that I've ever heard of changing gears causing any kind of mechanical failure.

They may be able to tell if the diff cover looks like it's obviously been removed when they see trucks every day that never have the diff covers removed.

The only other way they would know is by guessing based on your lift and tires or if they took the time to measure it out (you can determine gear ratio by how many turns the driveshaft does vs the wheels)

 

No. To use your wiper and motor example, this is how it works:
You: my wipers don't work.
Toyota: We checked it out and determined the super duper high coefficient wiper blade created too much drag and burned up the motor. Warranty denied.
You: Where's the proof?
Toyota: We have reason to believe this to be true. Warranty denied. If you want more, we go through arbitration and courts. Oh, by the way, your vehicle is now evidence and will be quarantined until the matter is resolved. Get your lawyer ready.
You: Nevermind.

What the MM will do is prevent Toyota from denying warranty on your rear diff because you installed those wipers. Basically it means just because you changed something unrelated they can't use that excuse. But if the mod and failure are in the same area... MM is no help. There is a very good example, written by a lawyer, of how it really works in the sticky threads above.