New gears ! - Jeep Wrangler Forum
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > TJ Jeep Wrangler Forum > TJ Tech Forum

Join Wrangler Forum Today


Reply
 
Thread Tools

Please support our sponsors and let them know you heard about them on WranglerForum.com
Old 10-04-2012, 10:20 PM   #1
Jeeper
 
lapis_blue's Avatar
 
Join Date: Sep 2012
Posts: 210
Images: 1
New gears !

Just went from 3.07 to 4.56 today and want a big difference ! 4.0L 5spd, I currently have 31's but going to 33's soon. Funny story was I didn't think about changing the speedometer gears and was going "65" on the highway and was actually going 45 hahah felt like an idiot good lesson learned

lapis_blue is offline   Quote
Old 10-05-2012, 06:10 AM   #2
Jeeper
 
TnDz TJ's Avatar
 
Join Date: Apr 2011
Location: Reno, NV
Posts: 2,925
Images: 220
it's like night and day.....makes you wonder why you waited, huh?

__________________
~Todd~ 2004 X 4.0 5 speed---SOLD
4" Lift, 4.56's, 33" Duratracs on M/T Classics
RR SYE, Tatton CV, MML, BL, TT, Dynomax Exhaust
Hella Lighting: Driving, Fogs and H4 E-Codes
NOPE! ... and NEVER will be...
TnDz TJ is offline   Quote
Old 10-05-2012, 06:20 AM   #3
Jeeper
 
BigDeaner's Avatar
 
Join Date: Mar 2012
Location: Boston
Posts: 614
How much did the regear end up costing you?
__________________
'99 TJ Chili Pepper Red SOLD
'13 JKU Rubicon Billet SOLD
BigDeaner is online now   Quote
Old 10-05-2012, 10:57 AM   #4
Newb
 
gunslinger9155's Avatar
 
Join Date: Sep 2012
Location: Denver, CO
Posts: 13
I have a 2.5L w/ 31's and regearing is high on my priority list as-is. That being said, the 'jeep-bug' has bit hard and tells me that some day I'll be into 33s...

If so, I'd like to re-gear just once and therfore am very interested in what you've done. My guess is that a stock SE probably has a similar ratio as yours.

You selected a 4.56 ratio. Is that the appropriate for the 31s you currently run or are you skipping ahead and gearing now for the bigger tires later?

Also, how many rpms are you turning at freeway speeds with the 31s and 4.56s?
gunslinger9155 is offline   Quote
Old 10-05-2012, 11:59 AM   #5
Supporting Member

WF Supporting Member
 
schnutzy's Avatar
 
Join Date: Sep 2009
Location: ring side seats to the the country's largest circus
Posts: 28,193
Send a message via AIM to schnutzy
Quote:
Originally Posted by gunslinger9155 View Post
I have a 2.5L w/ 31's and regearing is high on my priority list as-is. That being said, the 'jeep-bug' has bit hard and tells me that some day I'll be into 33s...

If so, I'd like to re-gear just once and therfore am very interested in what you've done. My guess is that a stock SE probably has a similar ratio as yours.

You selected a 4.56 ratio. Is that the appropriate for the 31s you currently run or are you skipping ahead and gearing now for the bigger tires later?

Also, how many rpms are you turning at freeway speeds with the 31s and 4.56s?
your 2.5 is a diferent beast that requires different things. as it came from the factory, you have 4.11 gears. much lower thatn the OPs 3.07s.
with the 2.5 motor, and if you want to go to 33s, 4.88 might be a better stepping stone than 4.56
__________________
clinging on to sanity, one motorcycle at a time.
schnutzy is offline   Quote
Old 10-05-2012, 12:10 PM   #6
Jeeper
 
cheap_jeep's Avatar
 
Join Date: Aug 2009
Location: Southeast PA
Posts: 63
I have a 2.5L and am running 4.88 gears. At cruising speeds I'm in the 2-2.5k region. Right where the 4 makes power.
__________________
97' TJ 2.5L Turbo 4.10's 33x12.50
68' M-715 258ci 5.86's 39x11(all stock)
But it's a peppy 4 cylinder!
cheap_jeep is offline   Quote
Old 10-05-2012, 12:54 PM   #7
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 35,395
Images: 2
Quote:
Originally Posted by schnutzy View Post
your 2.5 is a diferent beast that requires different things. as it came from the factory, you have 4.11 gears. much lower thatn the OPs 3.07s.
with the 2.5 motor, and if you want to go to 33s, 4.88 might be a better stepping stone than 4.56
Exactly, 4.88 would definitely be the right/most efficient gear ratio for that combination. 4.56 isn't enough gear for the 2.5L engine when talking 33" tires.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote
Old 10-05-2012, 03:48 PM   #8
Jeeper
 
lapis_blue's Avatar
 
Join Date: Sep 2012
Posts: 210
Images: 1
Quote:
Originally Posted by BigDeaner View Post
How much did the regear end up costing you?
Labor was 680$ for them to install it (not including gear price). Well worth the price because I wanted the warranty! The reason I went to 4.56 was for the 33's they are a little big for 31's for the idea ratio but still run just fine on the road. I canít tell you what my rpms are at speed because like I said before I have no idea how fast Iím going (speedo gear needs replacing) Iím also going to get a speedo gear for 33's so Iím sure it will still be all wacky for a while lol. there is some good graphs out there to see what you rpms will be with a gear and tire ratio if you need to find out what to expect but if you have 4.0L 5spd on 33's go for the 4.56 they are perfect I have 5th gear back lol!
lapis_blue is offline   Quote
Old 10-05-2012, 04:32 PM   #9
Jeeper
 
hmiller's Avatar
 
Join Date: Sep 2012
Posts: 266
would the gear ratio matter for the automatic 4.0l if i want to run 33's?
hmiller is offline   Quote
Old 10-05-2012, 04:52 PM   #10
Jeeper
 
lapis_blue's Avatar
 
Join Date: Sep 2012
Posts: 210
Images: 1
i think you need to run 4.11 for and automatic but im not sure, i only did the research for my jeep.
lapis_blue is offline   Quote
Old 10-05-2012, 07:43 PM   #11
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 35,395
Images: 2
Quote:
Originally Posted by hmiller View Post
would the gear ratio matter for the automatic 4.0l if i want to run 33's?
Yes it does and it also matters which automatic... the 3-speed used in 2002 and older TJs vs. the 4-speed that came in 2003 and newer TJs. If your TJ is a 2003 or newer, it needs 4.88 for 33" tires. If it's a 2002 or older, it needs 4.10 for 33" tires. There is a drastic difference in how those two automatics work which is why the big difference between the 4.10 and 4.88 recommendations for the same 33" size tire.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote
Old 10-05-2012, 10:52 PM   #12
Jeeper
 
hmiller's Avatar
 
Join Date: Sep 2012
Posts: 266
yeah i have a 2002.. thank you!!
hmiller is offline   Quote
Old 10-06-2012, 11:35 AM   #13
Newb
 
gunslinger9155's Avatar
 
Join Date: Sep 2012
Location: Denver, CO
Posts: 13
This is great information. Does anyone have a link to the graphs mentioned? I'd like to know if I'm going to be overreving my motor with the 4.88s during the 31/33 interim period.
gunslinger9155 is offline   Quote
Old 10-06-2012, 02:16 PM   #14
Supporting Member

WF Supporting Member
 
schnutzy's Avatar
 
Join Date: Sep 2009
Location: ring side seats to the the country's largest circus
Posts: 28,193
Send a message via AIM to schnutzy
Quote:
Originally Posted by gunslinger9155 View Post
This is great information. Does anyone have a link to the graphs mentioned? I'd like to know if I'm going to be overreving my motor with the 4.88s during the 31/33 interim period.
those graphs are very misleading if you dont read the fine print. better to use a gearing calculator. much less confusing.
i like this one: Novak Conversions - Gearing & Gearing Math for Jeeps

to figure out what numbers you need for your transmission, go here: http://www.wranglerforum.com/f5/tj-t...ecs-26347.html
__________________
clinging on to sanity, one motorcycle at a time.
schnutzy is offline   Quote
Old 10-06-2012, 03:10 PM   #15
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 35,395
Images: 2
Quote:
Originally Posted by gunslinger9155 View Post
This is great information. Does anyone have a link to the graphs mentioned? I'd like to know if I'm going to be overreving my motor with the 4.88s during the 31/33 interim period.
There is no such thing as "overrevving" it in that situation. The RPMs will be higher with the 31" tires but the additional RPMs won't hurt the engine. And be aware that if you do look up the RPMs on a chart, the vast majority of charts show the RPMs when the transmission is in in the gear that gives a 1:1 drive ratio which would be 4th gear if your transmission is the 5-speed. And just making sure your transmission is the 5-speed. 4.88 is correct for 33" tires with the 2.5L and 5-speed transmission. 4.56 would be correct for the 2.5L engine if the transmission is the 3-speed automatic.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote
Old 10-11-2012, 02:00 PM   #16
Newb
 
Join Date: Apr 2012
Location: Springfield, OH
Posts: 10
Quote:
Originally Posted by Jerry Bransford View Post
If your TJ is a 2003 or newer, it needs 4.88 for 33" tires.
What RPM could I expect to see cruising at 65 with this combo (03 Auto, 33", 4.88)? I was orignally leaning towards 4.56s, but now I'm not sure....

The Jeep will not be used for any aggressive wheeling (D30/35 limited), only the occasional back country hunting trail.
SleeperRam is offline   Quote
Old 10-13-2012, 09:53 PM   #17
Newb
 
letsgohunting's Avatar
 
Join Date: Jan 2012
Location: Mid Michigan
Posts: 11
I run 4.88 with 31's and love it, My 4 cyl 5 speed will run close to 3500 rpm at 75 mph ish. 3000 rpm is about 65 mph. I do not have to down shift on the highway going up hills now.
letsgohunting is offline   Quote
Old 10-13-2012, 10:08 PM   #18
Jeeper
 
tallzdatank's Avatar
 
Join Date: Sep 2012
Posts: 1,045
Quote:
Originally Posted by letsgohunting
I run 4.88 with 31's and love it, My 4 cyl 5 speed will run close to 3500 rpm at 75 mph ish. 3000 rpm is about 65 mph. I do not have to down shift on the highway going up hills now.
how does it change your fuel economy? my 4 cyl with stock gears I get around 22-25 highway. and about 20 in town. im thinking about regearing but don't know since its my dd.
tallzdatank is offline   Quote
Old 10-13-2012, 10:17 PM   #19
Jeeper
 
lapis_blue's Avatar
 
Join Date: Sep 2012
Posts: 210
Images: 1
Fuel economy, well u have to weigh that against tire size and f ur actually getting the power out of ur jeep u need or if ya under powered. If so get new gears u will lose a little on gas mileage but if u match it up with the chart it should put u close to stock again. Obviously bigger tires is a little less gas mileage
lapis_blue is offline   Quote
Old 10-14-2012, 10:40 AM   #20
Jeeper
 
tallzdatank's Avatar
 
Join Date: Sep 2012
Posts: 1,045
ive got 32s and want to switch to 4.88
tallzdatank is offline   Quote
Old 10-14-2012, 12:25 PM   #21
Knows a couple things...

WF Supporting Member
 
Jerry Bransford's Avatar
 
Join Date: Nov 2005
Location: Escondido, Calif.
Posts: 35,395
Images: 2
Quote:
Originally Posted by SleeperRam View Post
What RPM could I expect to see cruising at 65 with this combo (03 Auto, 33", 4.88)? I was orignally leaning towards 4.56s, but now I'm not sure....
Your engine RPM would only be 2229 at 65 mph with 33" tires and 4.88 gearing. Now you can see why we are recommending 4.88, even 2229 is barely enough for that big and heavy of a tire. The reason 4.88 is so strongly recommended is the 42RLE's overdrive ratio is an extremely steep .69 which lowers the RPMs much more than is healthy for the transmission and engine. Too low of an engine is not only unhealthy for the engine since an engine lugs at too low of an RPM, it is also not good for the transmission which is forced to work harder.
__________________
When you have a choice, buy American.

Jerry Bransford is offline   Quote
Old 10-14-2012, 04:54 PM   #22
Newb
 
letsgohunting's Avatar
 
Join Date: Jan 2012
Location: Mid Michigan
Posts: 11
my mileage went from 17.2 to 18.3 the only time I checked it. The 2.5 4cyl runs alot better on the highway.
letsgohunting is offline   Quote
Old 10-15-2012, 02:09 PM   #23
Newb
 
Join Date: Apr 2012
Location: Springfield, OH
Posts: 10
Quote:
Originally Posted by Jerry Bransford View Post
Your engine RPM would only be 2229 at 65 mph with 33" tires and 4.88 gearing. Now you can see why we are recommending 4.88, even 2229 is barely enough for that big and heavy of a tire. The reason 4.88 is so strongly recommended is the 42RLE's overdrive ratio is an extremely steep .69 which lowers the RPMs much more than is healthy for the transmission and engine. Too low of an engine is not only unhealthy for the engine since an engine lugs at too low of an RPM, it is also not good for the transmission which is forced to work harder.
That's what I was looking for. Low RPM lugging (equating to low line pressure) can certainly shorten clutch life.
__________________
2003 X, 4.0L, Auto, G2 4.88, 33" Wrangler Duratracs, 4" Fabtech, RE Tracbar, Energy Suspension bushings, JKS Quick Disconnects
SleeperRam is offline   Quote
Old 12-19-2012, 01:00 PM   #24
Newb
 
Join Date: Apr 2012
Location: Springfield, OH
Posts: 10
I got the 4.88s in a few weeks ago and I'm very pleased with ratio. The Jeep is much more enjoyable to drive now. Thanks, Jerry!

__________________
2003 X, 4.0L, Auto, G2 4.88, 33" Wrangler Duratracs, 4" Fabtech, RE Tracbar, Energy Suspension bushings, JKS Quick Disconnects
SleeperRam is offline   Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Download our Mobile App

» Featured Product

All times are GMT -5. The time now is 08:08 AM.


User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.

Jeepģ, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC