gear selection

[mossyoaktj]

im lookin at upgrading my gears in a few months i want to move to bigger tires. i run 33's now with a 373. but im lookin at ordering the 8.8 ready to bolt in from east coast gear supply (http://eastcoastgearsupply.com/i-276...-assembly.html) so i can get rid of my weak 35c. i want to wheel 36s and will most likely have another set to run on the street probably around a 34-35. trying to figure out which gear selection i need to go with. my jeep has the I6 and 5spd. i want something to meet in between a good trail gear and a good road gear seeing how i will have to drive from NC to Ohio a few times seeing how my next unit is in camp lejeune. and ideas. i already have a 373 an up carrier for the dana 30 which will be upgraded before too long if plans go as i want them

[blazerbrad]

My opinion for a daily driver is to gear it for optimal street use. Having the right axle gears for cruising on pavement and pulling grades on the freeway are much, much more noticable versus off-road when you can rely on using low range.

[Hope Springs Hauler]

I have 4.56 in mine. It is a good compromise. 4.88 would be good offroad and 4.10 would be a bit tall for the road.

[KargoMaster]

4.56 would also go well with my "why would you only go up one step" rule...

from 3.73... if 4.10 is good, then 4.56 has to be better...



my dos pesos

[mossyoaktj]

yea i was leaning towards 456 or 488. i have the 373 now with 33s and dnt mind them probably cause i just came from 307s but goin up to a 35 to 36 im regearing again when i get my 8.8 and what not. i just dnt want to go too deep into gears with it being a street trail vehicle.

[Trigger]

I had 4.10s in my Rubicon running 33s and wish I would have had 4.56s. Just a better gear for the application.

[flatlander757]

Run 4.88s...

I have 40s and 5.86s and it is freaking great... tons of power and can spin them at will.

Numerically, my ratio is identical to 33s and 4.88s...

Since you are planning on 35s-36s... then you DEFINITELY want as much gear as possible, if you didn't have the D30 I'd recommend 5.13s honestly.

FWIW I regear axles on the side... and when anybody asks me what gears to get they are like "really... that high?" When they are actually regeared, I get a thanks and none have had regrets yet.

Go 4.88s.

edit: which transmission do you have? If you have a manual w/ OD.. then I'll stick by the 4.88s...

but if you have the 3spd with no OD... then 4.56 would be better.

[mossyoaktj]

yea its the stock 5spd ax-15

[KennyTJ]

I have a HP30 and 8.8 in the TJ with the 4.0L and 6spd. I run 36" SX's on beadlocks offroad, and 35" BFG AT's on road. I have 4.10 gears, If not for the 6spd. with the lower first gear it would not be good off-road, even in 4LO. Honestly I liked the accelleration on the street better with 4.10s and 32" AT's. I am re-gearing mine to 4.88, much better for both on and offroad. Remember Jeep put 4.10s with 31's on the factory Rubicon with a 4:1 TC.

Go 4.88 you will be MUCH happier all around.

[mossyoaktj]

i wish i could find me the 6spd tranny for her alon gwiht the rubi t-case.

but 488 sound to be the way to go with 36's. how are 488s on highway speeds

[flatlander757]

Originally Posted by mossyoaktj

i wish i could find me the 6spd tranny for her alon gwiht the rubi t-case.

but 488 sound to be the way to go with 36's. how are 488s on highway speeds

Forget the 6spd... not enough gear in first vs the other transmissions to make it really worthwhile(5:1 vs about 4:1 in first gear)... Now if you get an SM465 or SM420 with the 7:1 first gear... then you're talking

For speeds and RPMs...

http://www.grimmjeeper.com/gears.html

You'll be great... 5.13s would be better but oh well.

People forget that when you add weight to Jeep it takes more force to keep it running on the highway... you need to keep the RPMs up higher than stock or else you'll be over-taxing the motor.

I turn 2300 rpms on the highway at about 60mph IIRC... with 40s and 5.86s I still manage to get 10mpg... considering I weigh WAY more than a stock TJ that's not bad at all.

[KennyTJ]

Originally Posted by flatlander757

Forget the 6spd... not enough gear in first vs the other transmissions to make it really worthwhile(5:1 vs about 4:1 in first gear)... Now if you get an SM465 or SM420 with the 7:1 first gear... then you're talking

For speeds and RPMs...

http://www.grimmjeeper.com/gears.html

You'll be great... 5.13s would be better but oh well.

People forget that when you add weight to Jeep it takes more force to keep it running on the highway... you need to keep the RPMs up higher than stock or else you'll be over-taxing the motor.

I turn 2300 rpms on the highway at about 60mph IIRC... with 40s and 5.86s I still manage to get 10mpg... considering I weigh WAY more than a stock TJ that's not bad at all.

In the TJ the 6spd. NSG370 has a whole gear lower than the AX-15 5spd. and it's a bullet proof tranny up to 300+hp.

[mossyoaktj]

i just need a gear that 5th wont kill me on the highway. but i may hold off and do th erear front and t case at the end of next year

[flatlander757]

Originally Posted by KennyTJ

In the TJ the 6spd. NSG370 has a whole gear lower than the AX-15 5spd. and it's a bullet proof tranny up to 300+hp.

Yeah... first gear is 5:1 in the 6 spd.

Better off getting a doubler or something... the 6spds have all kinds of stupid problems with synchros and crap.

I like my NV3550... I'd at least take this one over the NSG370... vs the AX15 I guess I wouldn't care either way.

Either way... with the AX15 and 36s and 4.88s you'll be at 2300rpms at 65mph which is perfect.

For the money... you'd probably be better off(when you do want more gear), doing a doubler or something... a 231-231 has been done, or a 231-300 flipped would save space... a 231-300 doubler is just as long as a bone stock NP231... or a couple inches longer than if you already did a SYE(which I'm guessing you already have).


Also.. while it's a moot point... the NSG370 has a LOWER OD gear than both the AX15 and the NV3550... it will run slightly higher highway RPMs... people always thing "oh 6 speed... yay gas mileage" haha.

[flatlander757]

Originally Posted by mossyoaktj

i just need a gear that 5th wont kill me on the highway. but i may hold off and do th erear front and t case at the end of next year

Yeah 4.88s will do that... I can hold 5th and accellerate fast enough on the highway without downshifting no problem.

[kb9qdi]

Originally Posted by KennyTJ

I have a HP30 and 8.8 in the TJ with the 4.0L and 6spd. I run 36" SX's on beadlocks offroad, and 35" BFG AT's on road. I have 4.10 gears, If not for the 6spd. with the lower first gear it would not be good off-road, even in 4LO. Honestly I liked the accelleration on the street better with 4.10s and 32" AT's. I am re-gearing mine to 4.88, much better for both on and offroad. Remember Jeep put 4.10s with 31's on the factory Rubicon with a 4:1 TC.

Go 4.88 you will be MUCH happier all around.

Ditto.....8.8 with 4.88's/D30 and a 6 speed. I'm at 2700 rpms or so at 65mph in 6th. Gobs of passing/hill power. Best $ I ever spent

I DD mine 40 miles a day getting 12-14 mpg depending on my foot. Don't fear the gear......you'll love it!

[bgwyllys61]

4.0 5 speed? 4.88s for sure, gives you growning room too