YotaBob

Is this possible or just dumb? Right now i have 4.10 diffs running 35" tires and I like the acceleration I get but have no top end (5th gear is useless unless going downhill on the freeway) and starting from a stop I have to wind the engine up pretty good and slip the clutch finely.

I'd like to run 4.56 or 4.88 gears on the street with the option of a 1.1 or 1.2:1 4 high gear and a 4.7 gear for 4 low

The truck is my daily driver. I would probably also use a twin stick to engage the 1.1:1, 2 high in 2WD for towing and hauling heavy loads

Is this possible with the design of the reduction box or is it physically linked 1:1? or would this effect my everyday driving without the transfer case?

Thanks

dropzone

iTrader: (6)

cool truck.
there is to my knowledge no kit (unless someone has done a custom machine set of gears) no alternative for high range on a toyota transfer case as a direct gear replacement like a rocklobster kit for a samurai.
there might be an under/over drive unit that could be used...

mastacox

Why not just run 5.29's?

There's no such thing as a transfer case that has a different gear reduction between 2-hi and 4-hi, so your options would be either dual cases or some sort of reduction unit like a Klune-V. 1.1:1 reduction is not low enough to be useful IMO, so you're better off just going with lower gears and using dual toyota x-cases. This would give you the option of 1:1, 2.28:1, or 5.19:1.

YotaBob

The truck is my daily driver and sole vehicle. I think 5.29's will be too low for the street driving. Using my calculations from my odometer vs GPS, 4.88 will be the closest match to stock power although they will be slightly undergeared but that is what I am wanting. I might even try 4.56 gears if I can get ahold a a complete third from Pull-A-Part

I want a truck with three "sets of gears" I want to be able to drive defensively on the street, have power on forest service roads/towing/hauling and crawl slowly over trail obstacles

I dont know anything about how a transfer case is designed so I was hoping someone had an idea about how this could be accomplished

4Crawler

iTrader: (3)

Can't re-gear the 1:1 high range because there are no gears there, it is just a direct shaft to shaft coupler in high range.

crolison

5.29's won't be too much, trust me. You'll really enjoy 5.29's.

4.88's will not be stock powered, your 35's are a lot heavier and have a lot more drag then your stock lil pizza cutters. it's just 200 more rpm from 4.88 to 5.29

I'm going 5.29's and 33's and i have at least 50 more hp than you, and i'm not complaining about high rev's.

Can you even use 5th gear anywhere? Do you get on the interstate? What's your top speed?

JeEVeS

As 4crawler stated. transfer case high (weather it 2 hi or 4 hi) is a dirrect connection. meaning the gear ratio is 1:1. same as 4th gear in a manual. direct connection from input shaft to output shaft. Personally i plan on 5.29 and i daily my rig.

On a personal wander, that i feel might be another couple steps from where your at. if you were to run duals (double tranfercase). scratch that, lest start with info.

stock tranfer case high 1:1, stock transfer case low 2.28:1 (on gear drivin cases, newer runners and v6 are slightly different).

taking my 4runner with 4.10 diffs, adding a dual case, front case with like a 1.2:1 ratio (not currently produced), rear case with a 2.28:1 or 4.7:1, or maybe even a third case with how ever low you wanna go. now highway driving would run stock 2wd high. FSR (fire service road) could go front case low. (the math isn't correct but a front case low that would simulate like a 5.71:1 diff). and then doucle front and rear or just run rear.

The similar thought would be to run yours diff's at 5.29 or 5.71 and make a tcase low range that was actually 1:1.2. as in over drive your low gear in the front case for highway driving. i think my other option is prolly more doable using a stock case. The reverse gear would make fitment an issue i believe.

This would all only be accomplished by a complete custom set of gears for your case. this is a far fetched idea and i don't see it coming to reality. Its from college dorm room days.

sorry for the rant but i always wanted to share that idea with some folk. Back on subject, my plan is 5.29, cause i drive at 60 down the highway at 3000rpm (22re) in 4th gear with 4.10 diffs and 34/9.5 tires. i belive 5.29 would allow me to use 5th gear while keeping my top speed. (assuming my top speed is limited by the brick of a front end that my 4runner has)

YotaBob

I do get on the freeway, I use 3rd for accelerating/hills and 4th for cruising. I shift at 3500 rpm usually cruise at 2000. Not sure of top speed but certain I could go 80+. I wouldn't want to because of braking limitations tho

The last post suggested I use 5.29s but you dont have them installed in your rig. I was planning on using a 4.88 diff out of a 3.0 auto to "test" it out if I can find one at a pull a part junk yard or craigslist

Anyone ever heard of someone using an overdrive on a truck? My understanding of an overdrive is its a separate reduction box mated to the transmission like a transfer case but with a different gear ratios. Seems like it could be done?

crolison

no one makes an overdrive for our trucks you'd have to run a different trans or tcase to do that.

Well you can buy loaded 5.29 diffs, they come up all the time on pirate. I bought my rear 5.29 elocker on pirate and its current in transit to me.

BLKNBLU

iTrader: (1)

I'd say give the 4.88s a try. I have recently finished with a build up that includes 35s and 5.29s. "Everyone" said that is the magic combo but now that I have it, I think it is too much. Driving around town it always seems whiny. Compared to my GPS my speedo runs about 5mph slow (i.e. speedo 50mph and actual speed 45mph). After the fact, I found these calculators:
http://www.4x4offroads.com/gear-ratio-chart.html

According to the first one I should gear to 4.94 based on current 35 inch tires and 235/75/15 from the factory. That is a lot closer to 4.88 than 5.29. Looking at some of the other calculators on that page it appears I could go to a 37-38 inch tire on my set up. Still thinking about that.

All that said, I just got back from a longish highway trip in the truck and there was still quite a bit of shifting to 4th and 3rd on the long steep uphill grades. Fortunately for me, it is mostly a weekend warrior and I don't have to drive it all day every day.

Give the 4.88s a try if you want to. Then report back to us with some real world results. Could be interesting. Good luck.

tc

I think this is perhaps the ultimate contradiction ever. How can you have good acceleration with having to start like that?

The reason you can't hold 5th is because your truck is geared too high.

Note that 99% of these charts and calculators are designed around V8 trucks with A LOT more torque than we have.

I run 4.88's with 33's, and wish I had done 5.29. That extra couple hundred RPM would be REALLY nice. These engines like to be tached A LOT more than they will stand being lugged. The powerband starts at 3000 RPM - anything below that and you are seriously wasting gas because you are applying A LOT more throttle than necessary on a properly geared vehicle. You get used to the RPM sound pretty quick - if you can't handle it, you need to sell your Yota and buy something else.

YotaBob

I have tons of acceleration in first after I get started moving, 2nd and third are fantastic as well. Essentially what I have is a 4 speed with a broken 1st gear.

I understand that my truck is geared too high, I am not an idiot. I will not be selling my "Yota" anytime soon either, bra. It will be buried with me.

My current thoughts are to run 4.7 gears in the X-fer case with 4.88 (or 4.56 gears) and buying another set of 31" or 32" tires for towing hauling


Has anyone ever tried to modify the high gear (straight shaft) in the transfer case to anything but 1:1 or is there no room for actual gears?

theAuthority

You actually have a 3 speed.... or a 5 speed with a broken 1st and failing 5th.

Don't call people "bra". We are not fabric that holds up breasts in cups. We are mostly men who hold up breasts with our hands.

JamesD

Your best bet Bob is a Chevy V6. You would get the same or maybe a little better gas mileage than you do now and more horsepower and torque.

YotaBob

I do not wish for petty bickering, insults or word picking. Please limit any posts to helpful advice or constructive criticism. Assume I have an IQ over 125

tc

Not to my knowledge. Most people just gear their trucks correctly and move on with life.

Guys with really big tires, where 5.71's won't cut it, have been known to use an arrangement like described in post 7 above, running around in stock low as high and then running a 4.7 case, or even a triple setup, for their low range.

theAuthority

If we assumed that you had an IQ of 125, we would have left your thread alone and let you figure it out yourself.

You posted here, you asked questions which can only be answered by telling you to get custom gears made for your t-case.

You then decided on 4.88's with 31" tires. Decent, but you're going to lose top end and highway driving.

Are you asking questions or just looking for a place to bounce ideas?

theAuthority

Best response yet

YotaBob

your use of the term "correctly" is subjective. Your opinion that 4.88 is too high (numerically low) of a gear for 33" tires is noted.

I cannot afford just to buy new 5.29 gears and hope that you are not just perpetuating De facto standard advice. I am very weary of your advice, tc because of your eagerness to insult me. My main use of the vehicle is transportation on surface streets and freeways.

I can easily afford to take a chance on the 4.56 and 4.88 gears because I can get them used from a junkyard

malteserunner

iTrader: (1)

You can also get used 5.29's off the net. I run 4.88's and 33's, and I kind of wish I had 5.29's. I only say that, however, because I'd prefer them off road. If you are just driving on the street then go ahead with the 4.88's (if you want). I think the 4.56 will still be too tall for your application. If I were in your shoes, I wouldn't even consider less than 5.29's with 35's. All this speaking from personal experience with the following setups: 4.88/33, 4.56/33, 5.29/33 and 5.29/35.