4.56 Re-Gear on 31s

Hello, TW peeps. I just finished my regear on my '03 PreRunner and wanted to give some feed back. So I originally had a 4.10 in the rear and was really struggling with overall drivability. I run LT265/70/17s. I decided to switch to a more aggresive gear since I struggle up hills and winding roads. I decided to go with a 4.56 because I will most likely stop at true 34s or 33s in terms of tire. When it came to what I did, it was a straight up overhaul. I swapped gears, new carrier and pinion bearings, new axle bearings, inner and outer axle seals, new crush sleeve and pinion seal. And yes, the left carrier bearing was barely spun, but that doesn't really matter. No matter how much you knurl the case, the bearing will spin. In terms of the end result, the truck drives pretty close to stock. I may have lost a bit on the highways, but overall, the truck drives great. I will refill my tank to compare gas mileage. I get about 200 miles in terms of range (Yea I know its pretty bad lol) however I think it will improve. I will know how it drives in the hills and mountains in due time as well.

 

Going from 4.10 to 4.56 don’t seem like much. Why not go straight to 4.88? I’m in the process of trying to regear my 03 prerunner too. I currently run LT285/75R16 is 4.88 gonna be too aggressive for it? Or should I go with 4.56 too?

 

Engine?

The question you should ask yourself is, will LT285/75R16 / 32ish~33" be the tallest tire you'll run. IDK about you but I do thing only once. Buy once, cry once.

 

My truck is 03 prerunner 3.4L v6 automatic. Currently at 4.10 with a factory elocker. Yes 285 is the highest I’ll go, no plan to go any higher. my mpg is horrible at the moment. I’m only getting around 12.0-15 mpg. I’m hoping 4.56 or 4.88 will help a bit.

 

I have factory 4.56s in my 3RZ double cab and am quite happy with them. Running 265/75-16. Turning at 3k at 80mph on the highway and enough to scoot around town if you use the go pedal. A 4.88 would put it in the sweet spot for around town and back roads but I do a lot of highway commuting so pretty happy with the 4.56 ratio.

 

IMO, for those of us who have the auto trans, it all comes down to the amount of weight you typically carry. Mine is 5800 lbs when fully loaded for an adventure. Extracab, v6, auto, 4x4 with heavy bumpers (front and rear) and winch, full skid plates and sliders, 285/70-17s currently. But I have run 33x10.5-15 and 255/85-16's too.

I have found 4.88s were not quite enough and I found myself wishing I had 5.29s. Don't get me wrong, 4.88s made a huge difference in driveability and even a slight improvement in MPGs. But the combination with added weight made it a touch sluggish and the trans started to hunt for gears again.

Since I'd already cried with the bill for regearing and front ARB locker, I didn't want to regear again. So instead I added the supercharger along with a haltech piggyback. Wow, I cried again but problem solved.

I guess my message to you would be, a little more gear with the auto is worth it.

 

Being a double cab, I assume you have an auto (all double cabs had autos from the factory). It's worth noting that the auto and manual have significantly different overdrive ratios.

W59 (4cyl manual) is 0.85:1
R150 (6cyl manual) is 0.84:1
A340 (4cyl or 5cyl auto) is 0.71:1.

Given the list of common Toyota 4x4 ratios (4.10, 4.30, 4.56, 4.88, 5.29), an auto should generally be one ratio lower than a manual for comparable driveability. In other words, if someone had the same truck but with a manual, they'd want 4.30 instead of 4.56 to keep similar RPMs on the highway.

You can see this in the factory-specced diffs: 3RZ auto trucks often got 4.56 gears while 3RZ manuals got 4.10 or 4.30.

 

I will be doing quite a bit of highway driving as well. I took that into account. I didn’t want to be doing nearly 3k while going 65

 

I regeared my truck recently, I have a single cab 3RZ auto, and was getting horrible gas mileage on my 285/75r16s (heavy tires).

The gear shop told me I'd be much happier with 4.88 over 4.56 gearing, and along with newer tires (255/75r16) it drives much better, more pep at lower speeds but still decent on the highway.

I have a camper shell along with storage drawers in the back, so I have at least 400lbs extra. I'm getting about 22mpg now.

 

I have an auto reg cab 3rz aswell was thinking 4.56 gears, currently on 4.10’s. Tires are 31” and set on that. My problem isnt much the city driving but the hwy. I always gotta put it on ect on any hill. Idk if its better to gear change or s/c it.

 

ECT only raises the shift point RPMs buy a couple of hundred. It does nothing once you are already in third gear or overdrive.

 

So your truck started with 4.56 and you went up to 4.88? What RPMs are you turning on the highway?

I just upgraded to 265/75/16s and it is a bit of a struggle on highways. I’m in a similar boat to Pauly wondering if I should regear or do the low boost SC.

 

Regear. Adding boost just puts more strain on the engine and drivetrain. Regearing takes the strain off the engine/ trans and drivetrain.

 

Good point there, should be cheaper as well.

 

Yes, I lied, I was at 4:30 stock with the 265s, and went to 4:88 and 32" tall tires, world of difference. 4:56 would have made it close to the stock ratio with the larger tires. I bought a used third member and had a shop do the upgrade, along with a TruTrac. All together it was probably $1k with parts and labor. I don't think you can do a SC for less than double that. Plus I get the benefit of the limited slip which helps me tons on the hilly road to my house.

 

Hmm ok. Yea, the SC seems to be $3k+, so definitely less cost efficient.

I already upgraded my truck to the Toyota E-locker, so I’ll probably get the Nitro Gear 4.56 kit and have a shop swap out the parts front and rear. The truck is definitely struggling with the 4.10s and auto.

 

If you're mechanically inclined and depending on the cost ECGS will do regears for $1k a diff with parts but you have to pull the diffs and mail them in.

 

Ohh so they’d do all the work and provide the parts? I installed the diff myself, so not worried about removing. I’ll look into them. Thanks!

 

Yep you tell them what you want and then you mail in your diff and they can re-gear it. They have a core setup too so you could order regeared diffs and pay a core charge then swap them out, and then mail your old diffs in to get your core charge back. This means no downtime waiting. Would also be a great time to get lockers installed.