Gearing

Spudcannons
BSJ 101 Planning Commitee
Posts: 231
Joined: Mon Mar 02, 2015 2:11 pm
Jeep Year: 2013
Jeep Model: JK Wrangler

Gearing

Unread post by Spudcannons »

I am unsure of what gearing to run with my 35"s and ATX slabs. They weight about 100 or so lbs 30+ over stock and I have 3.21 gears now, first is deep enough city driving is ok but the hunting and rather low highway rpm's are not. I am thinking of 4.56 4.88 or 5.13 anyone have any experiance with the 3.6l auto?
JKU Commando- I've tinkered with her a tiny bit.
User avatar
ASauer17
BSJ BOD President
Posts: 3151
Joined: Fri Apr 08, 2011 12:32 pm
Jeep Year: 1998
Jeep Model: TJ Wrangler
Real Name: Amanda
Location: Hubbardston ma

Re: Gearing

Unread post by ASauer17 »

I'm at 4.88 with 35s in a 4.0
98/99 TJ
2025 President
----------------------------------------
2023 & 2024 President
2021 Director of Events
2018 Secretary
2016 & 2017 President
2014 & 2015 Secretary
User avatar
Frank
Frankie BSJ Member
Posts: 4145
Joined: Sun Dec 27, 2009 8:54 am
Jeep Year: 1974
Jeep Model: CJ5

Re: Gearing

Unread post by Frank »

Im at 4.56 wishin I had 4.88s with a 4.7 , a 4 speed , and a 4x1 T-Case. So in low range its totaly awesome. I had said in another post for you to check a Tire/Ratio chart. I went from 3.73s to 4.56 but at the same time went from 32" to 35" and added only 300 rpm in high range. Trying to balance DD and wheelin is where you may have to make your choice. Id go one gear set over stock rpms for the tires you have or are planing to go to. 2 ratios at best to keep it streetable . FjR68
Spudcannons
BSJ 101 Planning Commitee
Posts: 231
Joined: Mon Mar 02, 2015 2:11 pm
Jeep Year: 2013
Jeep Model: JK Wrangler

Re: Gearing

Unread post by Spudcannons »

Frank wrote:Im at 4.56 wishin I had 4.88s with a 4.7 , a 4 speed , and a 4x1 T-Case. So in low range its totaly awesome. I had said in another post for you to check a Tire/Ratio chart. I went from 3.73s to 4.56 but at the same time went from 32" to 35" and added only 300 rpm in high range. Trying to balance DD and wheelin is where you may have to make your choice. Id go one gear set over stock rpms for the tires you have or are planing to go to. 2 ratios at best to keep it streetable . FjR68
What climb is that in your picture?
JKU Commando- I've tinkered with her a tiny bit.
User avatar
mrfreakinwhite
BSJ 101 Planning Commitee
Posts: 447
Joined: Thu Jun 27, 2013 7:15 pm
Jeep Year: 1998
Jeep Model: XJ Cherokee
Location: Lunenburg, MA

Re: Gearing

Unread post by mrfreakinwhite »

4.88s will make your MPG better and cause less strain in the drive line. The RPMs will seem a little high at first when you're on the highway, cruising, but it will put the engine in the sweet spot for getting you around. The V6, especially the 3.6L, likes a little more RPM than Jeep wants it to have, so you're goal is similar to stock gearing + a little extra.
4.56 is the LOWEST I would go.
5.13 is a little much but right around where you need to be for 37s. A friend has 37s and 5.13s on his 2008 auto and it is just a little more gear than a stock rubi on stock 32s with stock 4.10s. He's knocking down 18-20 mpg on the highway, but his total average economy is around 17mpg.
Spudcannons
BSJ 101 Planning Commitee
Posts: 231
Joined: Mon Mar 02, 2015 2:11 pm
Jeep Year: 2013
Jeep Model: JK Wrangler

Re: Gearing

Unread post by Spudcannons »

mrfreakinwhite wrote:4.88s will make your MPG better and cause less strain in the drive line. The RPMs will seem a little high at first when you're on the highway, cruising, but it will put the engine in the sweet spot for getting you around. The V6, especially the 3.6L, likes a little more RPM than Jeep wants it to have, so you're goal is similar to stock gearing + a little extra.
4.56 is the LOWEST I would go.
5.13 is a little much but right around where you need to be for 37s. A friend has 37s and 5.13s on his 2008 auto and it is just a little more gear than a stock rubi on stock 32s with stock 4.10s. He's knocking down 18-20 mpg on the highway, but his total average economy is around 17mpg.
That sounds pretty great. I got 17 MPG and under highway average with my stock gears doing 60-65. I need to figure out when to do the gears. I might as well do lockers and maybe a front axle at the same time. It's like 2600+ labor for the gears and lockers though.... :sad:
JKU Commando- I've tinkered with her a tiny bit.
User avatar
mrfreakinwhite
BSJ 101 Planning Commitee
Posts: 447
Joined: Thu Jun 27, 2013 7:15 pm
Jeep Year: 1998
Jeep Model: XJ Cherokee
Location: Lunenburg, MA

Re: Gearing

Unread post by mrfreakinwhite »

On a JK D30, I would want good shafts and a selectable locker, like an OX.
$2600 - a drop in the bucket.
Spudcannons
BSJ 101 Planning Commitee
Posts: 231
Joined: Mon Mar 02, 2015 2:11 pm
Jeep Year: 2013
Jeep Model: JK Wrangler

Re: Gearing

Unread post by Spudcannons »

mrfreakinwhite wrote:On a JK D30, I would want good shafts and a selectable locker, like an OX.
$2600 - a drop in the bucket.
I was thinking it may be worth wait and doing a prorock 44 front axle. Any more jeep mods means no MV Agusta F3 this year :doh:
JKU Commando- I've tinkered with her a tiny bit.
Post Reply