4.56 or 4.88

In the same boat. 295/75/16 k02 and 305/70/16 km3 v6 w/auto trans. I think im pretty heavy. front bumper(aluminum) with winch, rear bumper bumper with swingout, decked system, leitner rack, rtt, 63qt fridge, bed slide, heavy shadow awning 270 and camping stuff. Im leaning towards 4.88, but also have to drive on freeway under 80mph(since I have a baby now) to get to camping spots and going to tahoe. Camping spots are usually in norcal mountains or socal in desert. Hardest was miller jeep trail and octoillo wells trying to get to phone booth. Only ended up at the basket ball court. what would u guys recommend? no plans on going 35s yet

 

I went 456 on my 13 dcsb 4.0. The front has harrop e-locker and the rear has Detroit truetrac. The tires are 285 75 16 duratracs. The gearing I feel is right for 33’s. I have a bumper winch and armor coming and I think it should handle it well.

if 35’s and weight I would go 488.

 

Go 4.88 don't look back. You've got a ton of weight added and our baby v6 with auto tranny already pulls like a tired goat. Give Jus Differentials in Cashmere WA a call, they will sort you out.

 

When you guys are posting your setups make sure to mention whether you're running an automatic or manual since the are geared differently.

I placed my ECGS order last week and went with 4.56's and Harrop lockers. I know I'll be slightly over geared and will need to do lots of highway miles to get to camping/off-road spots but I'll take that for overall better drivability and great low speed control. My truck is heavy and not areodynamic and I plan on eventually towing a 12-14' inflatable boat.

6MT on 33's with full armor, roof rack, drawer system, lots of camping gear, fridge and extra fuel and water.

 

Will be going 35s soon. Still trying to decide on 4.56 or 4.88 for my auto. Don’t have a front or rear bumper but I’m planning on it eventually

 

I have an automatic

 

I hope I'm seeing this correctly. Using the chart from "West Coast Differentials" figuring @ 70 mph. & 33" tires & 4.56 gear, the MT W/OD runs 2600 rpm. while the auto W/ OD turns only 2275, that's 325 less with Auto. At 70 mph. & 33" tires & 4.88 the MT W/OD runs 2782 rpm. & while the auto. runs 2435 rpm., the auto with 4.88 is still geared 165 rpm. taller than a MT W/OD and with the 4.56 gears. Now 70 mph. & 33" tires & 5.29 gears, the MT W/OD runs 3016 rpm. but with the auto. W/OD runs 2639 rpm. If that's correct the auto. W/OD & 5.29 gears is very close, only 39 rpm. lower than the MT W/OD & 4.56 gears. With that much difference, it's just harder to imagine Toyota would put the same gears, 4.10, in all reg. cab 4X4's weather with MT W/OO or auto. W/OD. What am I missing????

 

4.0L V6
6MT RA60F
Kenda 35”

went 4.88
Makes me wonder if I should’ve gone less like 4.56

snapped dash pics from highway RPM
GPS 65mph


GPS 70mph


not sure exact RPM due to no scan gauge.
Can’t accurately gauge MPG due to city drives within break in procedure.

Oh well. Too late.

Otherwise crawling, off roading, city driving, power, going up hills, etc feels better. Feels better than stock. Feels like it’s not carrying a single pound of weight even though it’s actually carrying many pounds of weight.

Feels like it will tow better and handle taking on even more weight later.

am not against driving slower. Differs by area. Here in CA everyone drives faster so it puts me more in the right lanes. Don’t really have to watch your rear view as much there but cars likelier to smack into the side of you. Which is fine truck is armored.

traffic might not move as fast overall in other areas.

FJ cruiser manual RA61F has a different 6th gear said to be a better OD. According to Grimmspeed calculator that would drop highway cruising by 150 RPM. Thanks Toyota.
Am guessing the Kenda may not be a true 35 either and closer to 34 especially mounted and laden.
37 sounds sick but not the difficulties associated with fitting and making them work. Already have enough challenge fitting 35’s.

supposedly 4.88 has one less pinion tooth and is weaker than 4.56 which I found out later. Might not matter. Never heard of a real life 4.88 failure. Haven’t drank enough coffee to say let’s King of the Hammers When In Doubt Flat Out Send It

current stock RA60F may not be permanent. Seems some folks recommend swapping in a 3rd gen RC62F for better TOB design.
Going to research if it’s possible to swap in an FJ 6th gear and maybe replace synchros while at it.

current TOB is CM HydroTOB and still works. Picked up Tilton TW member adapter hardware kit to shelf for later in case it fails.

somehow threw off Speedo a lot, 10mph. Do 60 it says 70. Seems like fix is Hypertech behind cluster.

 

Use this calculator especially when you want to do comparisons. Gear Ratio Calculator (grimmjeeper.com) 4:56 would have been about 200rpm lower. You can also just download a MPH App onto your phone

 

I did. Supposedly the calculator isn’t 100% accurate and doesn’t take things into account such as real life tire size versus theoretical exact number.

Sorry may have mistyped as Grimm speed. Used that Grimm calculator to plug everything in such as tire size, engine, trans, etc

might be fine. Truck isn’t really sped, not built for it, and the power may be useful if ever driving through or living in altitude.
Not to mention the possible ability to change trans or 6th.

super fantastic MPG probably impossible to obtain regardless. Basic inefficient motor design, high drag coefficient, tire wind resistance, lift height, etc all things regear doesn’t change.
Any armor such as skids were chosen for strength and cost ie 1/4” steel seeming more durable than costlier 3/16” aluminum.

 

I have the AT (vs MT) and have driven 1k miles back and forth from TX to CO 3-4 times since replacing my HG with my RPMs sitting in that 2700 range for hours and hours ... zero issues. Everytime i'm in the dirt or snow I remember why I went with 488s and would do it again. Once you get to this point (35s, armor, who knows what in the bed, etc.) I'd throw out any thoughts about mpg. Take a look at the Dakota Digital or search on here -- it looks to be a solid proven way to fix the odometer with hte new tires. I have one sitting in my garage waiting for free time.

 

I have tried finding info on how to install a Dakota Digital on a 2nd gen couldn't find anything solid. I've used them on a couple first gens and they worked great and are super simple to adjust once wired up correctly. Have you been able to find out how to wire them into a 2nd gen? I have stock gears still with 34's and I'm about 5mph off at around 70-75mph.

 

I have this thread bookmarked for when I find the time. I haven’t read it in forever but I think it covers it.

https://www.tacomaworld.com/threads...-an-easy-alternative-to-the-hypertech.622313/

 

Question is rather than 4.88 crawl would it have been better to 4.56 and later rely on a dedicated crawlbox to crawl.

rather than sacrifice daily most of the year on road performance including far drives to get to and from a trail.

 

I went 4.56 with skinny 33s, and felt I was overgeared. Moved to Kenda skinny-ish 35s, it's probably a little overgeared, but I generally don't have complaints. Drove about 10,000 miles on each so far, including trips to/from Colorado and Utah and plenty of trail time in the Sierras, CA/NV/UT deserts, and Rockies. I think that if I didn't do as much highway driving to/from my destinations, 4.88 would probably make more sense. On a V6 4.0 auto with a tonneau, bedrack, and lightweight RTT, BTW.

edit: Or maybe it was 20,000 on the 33s.

 

seems like auto 5th is probably lower RPM than manual 6th

 

As a point of reference on the relationship between gearing, tire size, weight, drag, and gas mileage since I bought the truck. YMMV, literally.

 

Definitely a personal choice but hard to know until it’s done. Me - I love the idea of 488 WITH the crawl box. And sas hahaha. Someday.