Thoughts on 4.88 vs 5.29 longevity

I'm currently researching the pros and cons of 4.88 and 5.29 gear ratios. So far, I've read mostly favorable anecdotes on 5.29, however, I'm looking to hear the drawbacks as well (if any).

I use my truck ('17 TRD PRO Crewmax) as a daily driver as well as a weekend adventure vehicle for trips in the AZ wilderness. I also tow (~3500-6000lb) maybe once or twice a year. I favor durability and longevity as much as well execution. I will be running 315/70/18 tires with JBA UCAs and TRD PRO suspension with Coachbuilder shims. I'm looking for a well-rounded application as I use my truck for everything.

Looking for some objective (and a few subjective) thoughts for everyone who's much more experienced and knowledgeable than I am. Thanks

 

The 5.29 uses a smaller pinion which makes it more susceptible to failure if abused. In your particular use case I'm not sure I would even be considering a regear, it would come down to how long I would own it and what else I would likely be doing in the future with it. Does it feel underpowered to you? Are you sure the rest of the drivetrain is in good working order, like good clean intake system, clean injection system, clear exhaust, etc? Some people buy the pedal response improvement devices, seems silly to me, but whatever. Lots of stuff to consider and maybe even do more homework on. I would start with freshening up the powertrain if it hasn't been done yet for awhile.

 

I don't really notice a loss in power right now but I'm currently on 295/70/18. In the next few months I'll be moving up to 315/70/18 which are 35.7" (Toyo Open Country M/T) in diameter. Most of what I've read indicates a re-gear is required for when tires sizes are increased above 35". Most of the gear ratio charts I've seen indicate I should go with 4.88 but most in this forum say to go with 5.29. I do plan on owning as long as I possibly can.

 

I'm also in a situation of being somewhat torn between the two with 285/75 18's. For the best overall results with all of the different factors considered I will be doing the 5.29's and most likely a front only Eaton locker. Good luck!

 

I'm curious as to why you're going with front-only locker and not rear. Any particular reason?

 

Cost vs benefits. Most of the time I ever needed 4wd in my life, I needed the front end action! The more ability the front has to forge ahead the better, and the rear has the factory system that uses the brakes to sort of assist already in place. Generally speaking I am old enough and experienced enough in my life to know my limits and most of my recovery equipment is just in case of something unforeseen happening or to assist someone else caught up in a mess.

 

I’ve tried both with that tire size. 5.29 has zero drawbacks. That’s the recommendation.

 

What brand and why? REM polished or not? Different brand front/rear or match? Any favorite oils, maybe even different front/rear? I'd like to make the best overall selections and always appreciate your contributions to the discussions here.

 

@2mchfun I don't mean to de-rail the convo but what does "REM polished" mean?

 

Sierra because they get orders right. No need for rem. Any oil, the thickest possible in your weather conditions. Same front and rear

 

It's a surface polishing process that generally produces a better surface than traditional machining is capable of producing. Sort of a pre wear in process that helps minimize surface imperfections.

 

Only drawback imo to 5.29s is your top speed is limited without flashing the truck.

 

Is that not part of the installation process?

 

No, installing gears only involves the differentials. Getting the ECU flashed would be a separate process, and one I highly recommend in general for drivability, but they're separate modifications.

 

https://youtu.be/bZMlRnUwaao

I've got mine REM'd and cryo, no drawback, only positive.

- accelerate quicker
- tows better
- makes transmission feel better
- way better mpg during towing.

there's a GB for regearing right now, that cost is insanely cheap.

 

Thanks for the info all! It's very helpful. What's the best way to get the ECU flashed to reflect the new gear ratios?

 

I’m in AZ with a 4.6L, 4.88’s and 37’s if you want to try it out. If I could have done 5.29’s with the 9.5” rear end, I would have. But drivability wise, the 4.88’s have been solid and I can still burn rubber if I want to waste money.

Eventually I may buy a used 10.5, truss it and throw 5.29’s and a Powertrax in. But for now, I’m fine.

 

Nice feedback, thanks. Do you know the most reputable shop in AZ to get new gears installed?

 

Honestly I don’t. I did them myself, it’s not a horrible job if you get the install kit and have someone with you that has set some gears up before. I went with Nitro and replaced all bearings and seals just because I was in there.

You need to shim the pinion, but the rest is adjustable. Since you can remove the entire 3rd member, you can set it all up on a work bench. Here’s an example of the adjustable cups.

It’s an expensive job the mess up, but if you have patience and time, you can save a lot of money doing it yourself.

 

Also, my 2 cents, if you’re going to pay to get it done, you may as well do a Powertrax or other locker at the same time. It *shouldn’t* add to labor cost and you won’t want to do it again OR pay for it again.

 

Is an ECU refresh and a tune the same thing? I see some mentions of "tuning" the truck once a re gear is done but I don't really understand what is being talked about.

I would imagine changing something as drastic as the gear ratios in the differential would affect some of the electronic tuning/controls of these trucks.

 

5.29's for sure!

Agreed, it was actually kinda fun! If anyone is in the Indianapolis area and wants the tools to do it, I may be interested in selling off everything I procured to make the job easy.

https://frugalfill.com/diy-2nd-and-2-5nd-generation-toyota-tundra-differential-regear/

 

Correct, tuning, flashing, etc. Are all the same thing. In general regearing doesn't require any tweaking of other systems of the truck. The abs sensors pull from the hub itself, and then the truck knows the transmission parameters, and those two systems don't seem to be very intertwined so what happens between the trans output and the wheel doesn't matter that much.

The only downside seems to be that 5.29s have a reduction in the speed governor for some reason, which can be removed with a tune. But abs, atrac, etc all behave normally.

 

Gotcha, thanks for the 'splanation!

 

Ken @ Gearinstall

http://www.gearinstalls.com/

I sent my diffs from Canada to him, this man has provided the best service I've ever received in automotive industry.

 

I would talk with Ben McCalley at Arizona Toy Pros in Mesa. They did my gears and I never looked back

Arizona Toy Pros
63 E McKellips Rd, Unit 123
Mesa, AZ 85201
(480)687-4118

 

I'm in almost the exact same boat and can't seem to get convinced either way. Consensus seems to be 50/50 split. I know 5.29 will be great for towing, but a little worried about daily driving. Still, i think I'm leaning towards 5.29... though kinda wish I could test drive a truck with them real quick for some assurance.

 

It’s not split, I promise you. I’ve hosted hundreds of gear jobs and sold thousands. You’ll regret getting 4.88 when you could’ve got 5.29

 

All my research points towards 4.88. Even this calculation tells me going up to 315/70R18 would put me at 4.78 as my new target ratio. Most of the feedback I've read on 5.29s has been mostly anecdotal.


https://www.intercotire.com/tire_size_change_gear_ratio_calculator

Same goes for charts like this:

 

For sure that's the type of stuff that makes me wonder about and flip to 4.88....but then you read about our specific trucks, things like our adaptive ECU and how even though engine revolutions may go up, engine load actually goes down with 5.29s and makes me flop back.

Correct me if I am wrong, but don't our trucks come stock with 4.30? That seems fairly steep for a stock half ton. Also, believe my truck came stock with 32" tires, in which 4.30 gears would be way off based on that chart. All of which leads me to think our trucks lean towards steep gears as designed. But I really don't know much