4.56-4.88

4x4JeePmaNthINg · Oct 20, 2016

4.56-4.88 regear. I plan on 33s or 35s but currently i plan to keep a set of 31" duratracs for the fall/ winter months. I wish they made them in 33x10.50:roll:
I read a few posts that say they dont mind 31s with 4.88. is this madness or not too far fetched? my rig is a dd and i typically drive 60mph daily until snow flys.

99 np242, aw4, hpd30 c8.25

rockclimber · Oct 20, 2016

are you doing the work yourself or do you have a friend/shop that can do it cheaply?

if so, then go 4.56 until you go to 35"s then regear to 5.13.

cal · Oct 20, 2016

On the left, 4.88 and 31's. On the right, 3.55's and 31's.

Note that 3rd gear with 3.55's is close to 4th with 4.88's. If you want to find out how tolerable it would be, run around in third gear for a week and see how you like it.

dan1977p · Oct 20, 2016

I'm running 4.88 on 33's and 3000rpm at 80 isn't bad as long as your driveshaft is balanced. Off road in 4L, my top speed is about 35.

Boostwerks.com · Oct 20, 2016

dan1977p said:
I'm running 4.88 on 33's and 3000rpm at 80 isn't bad as long as your driveshaft is balanced. Off road in 4L, my top speed is about 35.

Is that calculated or have you actually hit 35mph in 4L? :looney:

cal · Oct 20, 2016

I've definitely hit 40 mph in 4-low.

But I have a 3.8:1 low range...

dan1977p · Oct 20, 2016

Boostwerks.com said:
Is that calculated or have you actually hit 35mph in 4L? :looney:

According to LeadNav I have, but the motor screams for me to stop. :flame:
I don't recommend it.

Boostwerks.com · Oct 20, 2016

Yeah mine sounds like a freight train at 5mph. Going 40 and letting off the throttle must feel like your hitting a brick wall.

cal · Oct 20, 2016

no more so than punching the gas in low range.

rockclimber · Oct 20, 2016

with 4.56 gears and 35"s I can hit 30-40 in low pretty easily.

I don't like to do it because its not good for the planetaries, but I have done it.

TRCM · Oct 20, 2016

rockclimber said:
I don't like to do it because its not good for the planetaries, but I have done it.

Why is it not good ??

blakews2217 · Oct 20, 2016

TRCM said:
Why is it not good ??

Don't quote me on this but I think It's bad for them because they are spinning super fast and makes excessive wear. I saw someone who killed there tcase from it. The planetary and sun gears became shrapnel and break the housing. Couldn't move him with the driveshafts in. But stock Iv let out at 35 because my poor stroker was screaming murder.

srb531 · Oct 20, 2016

rockclimber said:
are you doing the work yourself or do you have a friend/shop that can do it cheaply?

if so, then go 4.56 until you go to 35"s then regear to 5.13.

this is not good advice,unless you like spending money & doing things twice.

rockclimber · Oct 20, 2016

srb531 said:
this is not good advice,unless you like spending money & doing things twice.

no.

that is why I specifically said "are you doing the work yourself or can have it done cheaply?"

running 4.88 gears on 31"s on a DD is bad advice.

TRCM · Oct 20, 2016

blakews2217 said:
Don't quote me on this but I think It's bad for them because they are spinning super fast and makes excessive wear. I saw someone who killed there tcase from it. The planetary and sun gears became shrapnel and break the housing. Couldn't move him with the driveshafts in. But stock Iv let out at 35 because my poor stroker was screaming murder.

Why wear ?? not enough lubrication @ that rpm ??

Why would it be any worse than the planetaries in the transmission ?? The ones in the tcase would actually be spinning slower by whatever ratio the tcase is.

I can see it is there's no lubrication tho....

4x4JeePmaNthINg · Oct 23, 2016

on 3.73 and 32s, 80mph highway is just below 3000rpm and usually anything above 70 is begging for on/off overdrive. I have the np 242 but when you all are saying you can go 30-40 in low range I can't imagine how or why you would? Your vehicle should sound like it's about to explode right?

Upon putting around in 3rd I can say 4.88s and 31s would leave a lot to be desired if I ever planned on 50mph+. How well will 4.56 or 4.88 even out with 33s?
32+3.73 just start making the trans unhappy. I would hate to rehearsal to 4.10 and just barley be happy on 33s

cal · Oct 23, 2016

4x4JeePmaNthINg said:
. I have the np 242 but when you all are saying you can go 30-40 in low range I can't imagine how or why you would? Your vehicle should sound like it's about to explode right?

Because king of the hammers baby

Sometimes being 1 second faster to the next rock is the difference between 1st place and 3rd place.

rockclimber · Oct 23, 2016

4x4JeePmaNthINg said:
Upon putting around in 3rd I can say 4.88s and 31s would leave a lot to be desired if I ever planned on 50mph+. How well will 4.56 or 4.88 even out with 33s?
32+3.73 just start making the trans unhappy. I would hate to rehearsal to 4.10 and just barley be happy on 33s

with an auto, 4.56 and 33/32" tires was as close to a perfect match as I think is possible.

Your vehicle should sound like it's about to explode right?

lets be real, Cal's rig always sounds like that.

trippled · Oct 24, 2016

4x4JeePmaNthINg said:
on 3.73 and 32s, 80mph highway is just below 3000rpm and usually anything above 70 is begging for on/off overdrive. I have the np 242 but when you all are saying you can go 30-40 in low range I can't imagine how or why you would? Your vehicle should sound like it's about to explode right?

Upon putting around in 3rd I can say 4.88s and 31s would leave a lot to be desired if I ever planned on 50mph+. How well will 4.56 or 4.88 even out with 33s?
32+3.73 just start making the trans unhappy. I would hate to rehearsal to 4.10 and just barley be happy on 33s

You're not having enough fun. I hit 40 all the time. I'm not going to stop and shift the tcase Everytime I hit a little easy section.

VAhasnoWAVES · Oct 25, 2016

TRCM said:
Why wear ?? not enough lubrication @ that rpm ??

Why would it be any worse than the planetaries in the transmission ?? The ones in the tcase would actually be spinning slower by whatever ratio the tcase is.

I can see it is there's no lubrication tho....

i would imagine proper fluid level is important.

i know there are oiling issues with the tera low kit. they even specifically say its not for high speed use due to starvation. but i havent seen issue with normal planetary gears. ive bombed around in the sand dunes in low without issues... but my jeep tops out well before 50 mph. (manual, 5.13s, and 35s)

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