Gearing/MPG - 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 03-16-2015, 05:50 PM
Thread Starter
  #1
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Gearing/MPG

I got my 2000 4.0L 5 Speed Sport back in August and have just been driving it and not worrying about gears and other mods. Now I have been looking around and am starting to get questions. I believe that it is lifted 4" with 31" tires. Eventually I want to get 33s I think it has stock gears, looked for the code earlier but it was too dirty to see and I'll check it again tomorrow. Will 4.56 gears help me on the highway with maintaining speed in 5th gear or would I still have to downshift (I think I have 3.07)? Would it hurt mpg or not change it? Right now I'm getting 10. And how much do good gears cost? Any extra help/info is greatly appreciated! Let me know if you need more info and sorry about the length.

TJ_Joe is offline   Quote
Old 03-16-2015, 06:05 PM   #2
Jeeper
 
AUJeeper's Avatar
 
Join Date: Dec 2014
Location: Macon, Ga
Posts: 233
Quote:
Originally Posted by TJ_Joe View Post
I got my 2000 4.0L 5 Speed Sport back in August and have just been driving it and not worrying about gears and other mods. Now I have been looking around and am starting to get questions. I believe that it is lifted 4" with 31" tires. Eventually I want to get 33s I think it has stock gears, looked for the code earlier but it was too dirty to see and I'll check it again tomorrow. Will 4.56 gears help me on the highway with maintaining speed in 5th gear or would I still have to downshift (I think I have 3.07)? Would it hurt mpg or not change it? Right now I'm getting 10. And how much do good gears cost? Any extra help/info is greatly appreciated! Let me know if you need more info and sorry about the length.
Gears would help and 4.56 would be the correct ratio for 33's. Cost for regearing can vary-I would call around but it should be somewhere around $500/axle but there will be a ton of varying opinions on that. As far as gas mileage goes you should be able to improve on your current but not much-a jeep is as aerodynamic as a barn door

AUJeeper is offline   Quote
Old 03-16-2015, 07:06 PM   #3
Mostly old school..!

5-Year WF Supporting Member
 
Water Dog's Avatar
 
Join Date: Mar 2011
Location: Now searching for rocks in Sumner, TX
Posts: 12,149
As AUJeeper suggested, 4.56 would be the right gear ratio for 33's with your 4.0L and 5 speed, but it would be pretty deep for 31's. If you will definitely be going to 33's, I would hold off on the regearing until you do. I think you will find that $500 per axle won't do it for a shop to supply parts and labor any more. More likely, you will probably be paying in the $1600 range for both axles, parts and labor.

On the other hand, if you plan on staying with 31's, just go ahead and have it regeared to 4.10's.
__________________
Dennis
Water Dog is offline   Quote
Sponsored Links
Advertisement
 
Old 03-16-2015, 10:23 PM
Thread Starter
  #4
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Thanks for all of the information guys! Sorry if it was all out of order, I do my best to organize it but it doesn't always work out. I would most likely just buy the parts and have my dad help me. Is there a way that I can make it limited slip or not? If this helps at all in my way home from work tonight I hit 70 in 4th and it was at 2,500 rpm. If I think of anything else I'll post it. And thanks again for the great help.
TJ_Joe is offline   Quote
Old 03-16-2015, 10:35 PM   #5
Mostly old school..!

5-Year WF Supporting Member
 
Water Dog's Avatar
 
Join Date: Mar 2011
Location: Now searching for rocks in Sumner, TX
Posts: 12,149
Quote:
Originally Posted by TJ_Joe View Post
Thanks for all of the information guys! Sorry if it was all out of order, I do my best to organize it but it doesn't always work out. I would most likely just buy the parts and have my dad help me. Is there a way that I can make it limited slip or not? If this helps at all in my way home from work tonight I hit 70 in 4th and it was at 2,500 rpm. If I think of anything else I'll post it. And thanks again for the great help.
Sounds like you're current gearing is most likely 3.07. Unless your dad has regeared differentials before, plan on letting a shop do it. There is a lot more to setting up new gears than just replacing parts, and if done wrong it can wind up costing way more than a shop regear job.
__________________
Dennis
Water Dog is offline   Quote
Old 03-16-2015, 10:41 PM
Thread Starter
  #6
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Quote:
Originally Posted by Water Dog View Post
Sounds like you're current gearing is most likely 3.07. Unless your dad has regeared differentials before, plan on letting a shop do it. There is a lot more to setting up new gears than just replacing parts, and if done wrong it can wind up costing way more than a shop regear job.

Ok, thanks. Is there a way to make both axles have limited slip or not?
TJ_Joe is offline   Quote
Old 03-16-2015, 11:49 PM   #7
Jeeper
 
CarolinaBound's Avatar
 
Join Date: Jun 2012
Location: Langhorne, PA
Posts: 1,505
If he's sticking to 31s and goes 4.10s, it'd probably be cheaper to just swap axles. Should be able to pick up a pair of axles from a 4 banger TJ for under $500. Hell people give away D35s. Low pinion D30s are easy to come by, too.
__________________
Poverty/College Budget 2004 TJ 2.5" RC coils, 1.25" BL, M95 shocks 4.5" up 4.75" down travel front, 4.7" up, 5.3" down rear

Live around Philly or south Jersey? Come wheeling or wrenching! Look in here \/\/\/
https://www.wranglerforum.com/f97/phi...o-1129778.html
CarolinaBound is offline   Quote
Old 03-17-2015, 12:20 AM   #8
Mostly old school..!

5-Year WF Supporting Member
 
Water Dog's Avatar
 
Join Date: Mar 2011
Location: Now searching for rocks in Sumner, TX
Posts: 12,149
Quote:
Originally Posted by CarolinaBound View Post
If he's sticking to 31s and goes 4.10s, it'd probably be cheaper to just swap axles. Should be able to pick up a pair of axles from a 4 banger TJ for under $500. Hell people give away D35s. Low pinion D30s are easy to come by, too.
Very true
__________________
Dennis
Water Dog is offline   Quote
Old 03-17-2015, 01:03 AM   #9
Jeeper
 
reb6672's Avatar
 
Join Date: Feb 2015
Location: Northern NJ
Posts: 207
If you're only getting 10mpg now with 3.07's and 31s, something else sounds wrong to me. I was averaging 14/15 with 3.07s and 30's on my 4.0 with a 5spd. Last week I put in new spark plugs, air filter and changed the oil, and now I'm averaging just a little over 17mpg..I do alot of highway miles though and I'm not that heavy on the gas pedal.

I know none of that is related to gearing, but if you haven't changed the plugs and air filter since you bought it in August, I would do it now regardless. It might help a little, but at least now you'd know it was recently done and can keep track for when you have to do it again.
reb6672 is offline   Quote
Old 03-17-2015, 06:24 AM
Thread Starter
  #10
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Quote:
Originally Posted by reb6672 View Post
If you're only getting 10mpg now with 3.07's and 31s, something else sounds wrong to me. I was averaging 14/15 with 3.07s and 30's on my 4.0 with a 5spd. Last week I put in new spark plugs, air filter and changed the oil, and now I'm averaging just a little over 17mpg..I do alot of highway miles though and I'm not that heavy on the gas pedal. I know none of that is related to gearing, but if you haven't changed the plugs and air filter since you bought it in August, I would do it now regardless. It might help a little, but at least now you'd know it was recently done and can keep track for when you have to do it again.
I do also drive in the city most of the time too. And eventually I want to get 33s. Could I keep the 3.07 gears with 33s until I can afford 4.56?
TJ_Joe is offline   Quote
Old 03-17-2015, 06:43 AM   #11
Jeeper
 
Clay T 66's Avatar
 
Join Date: Aug 2013
Location: Mercer Co. Ohio
Posts: 8,463
Quote:
Originally Posted by TJ_Joe View Post
I do also drive in the city most of the time too. And eventually I want to get 33s. Could I keep the 3.07 gears with 33s until I can afford 4.56?
You can run 33/3.07. I ran 32s with 3.07 for a year and now 33s with 3.07 for three months but let me tell you, it sucks. It's defiantly doable though. I've got 4.56s waiting to get installed right now.
Clay T 66 is offline   Quote
Old 03-17-2015, 07:35 AM   #12
Jeeper
 
Ryan Angela's Avatar
 
Join Date: Sep 2013
Location: Yorkville IL
Posts: 1,815
Quote:
Originally Posted by TJ_Joe View Post

Ok, thanks. Is there a way to make both axles have limited slip or not?
Yes. When having them regeared, you can add limited slip, or a locker.
__________________
'01 60th anniversary ed. TJ 4.0 3 speed auto, 3.5" susp lift, 1" MML, 1.25" BL 33X12.5X15 MTR's, weekend toy.
Ryan Angela is offline   Quote
Old 03-17-2015, 09:58 AM   #13
Mostly old school..!

5-Year WF Supporting Member
 
Water Dog's Avatar
 
Join Date: Mar 2011
Location: Now searching for rocks in Sumner, TX
Posts: 12,149
Quote:
Originally Posted by Ryan Angela View Post
Yes. When having them regeared, you can add limited slip, or a locker.
Just don't lock a D35.
__________________
Dennis
Water Dog is offline   Quote
Old 03-17-2015, 10:01 AM
Thread Starter
  #14
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Quote:
Originally Posted by Water Dog View Post
Just don't lock a D35.
Is there a code that can tell me if I have the D35? And why not?
TJ_Joe is offline   Quote
Old 03-17-2015, 10:17 AM   #15
Commercial Member

5-Year WF Supporting Member
 
Shark_13's Avatar
 
Join Date: Dec 2012
Location: Idaho
Posts: 6,859
Quote:
Originally Posted by TJ_Joe View Post

Is there a code that can tell me if I have the D35? And why not?
You can get a copy of your build sheet off the jeep website.
Otherwise just crawl under and look. Dana 35 is a perfect oval shape with a rubber fill plug (if factory cover).
__________________
One-of-a-kind wood shift knobs for sale

https://www.wranglerforum.com/f37/han...s-1175625.html
Shark_13 is offline   Quote
Old 03-17-2015, 10:34 AM
Thread Starter
  #16
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Quote:
Originally Posted by Shark_13 View Post
You can get a copy of your build sheet off the jeep website. Otherwise just crawl under and look. Dana 35 is a perfect oval shape with a rubber fill plug (if factory cover).
Okay, and is there a reason to not lock it?
TJ_Joe is offline   Quote
Old 03-17-2015, 10:43 AM   #17
Jeeper
 
CarolinaBound's Avatar
 
Join Date: Jun 2012
Location: Langhorne, PA
Posts: 1,505
Quote:
Originally Posted by TJ_Joe View Post
Is there a code that can tell me if I have the D35? And why not?
Should be a tag hanging off the cover or it'll be engraved somewhere. Can't remember off the top of my head. Google should tell you.

Don't want to put in a locker because the Dana 35 is a relatively weak axle as is. 33's are considered it's "safe limit" if you don't want to spit out the spider gears or snap a shaft. Been on 33's with the factory Trac loc LSD for over a year with no issues. Can lock the front Dana 30 and be OK, though.

Just did a quick search on craigslist and you can easily get a front and rear axle with 4.10's for $300. Nothing else will bet his cheap. Can add a $200-300 lunch box locker to the front if you wish. If you want to lock the rear it's time to start looking at 8.8s, 44s, etc.
__________________
Poverty/College Budget 2004 TJ 2.5" RC coils, 1.25" BL, M95 shocks 4.5" up 4.75" down travel front, 4.7" up, 5.3" down rear

Live around Philly or south Jersey? Come wheeling or wrenching! Look in here \/\/\/
https://www.wranglerforum.com/f97/phi...o-1129778.html
CarolinaBound is offline   Quote
Old 03-17-2015, 10:57 AM
Thread Starter
  #18
Jeeper
 
TJ_Joe's Avatar
 
Join Date: Mar 2015
Location: Hooksett, NH
Posts: 212
Okay thank you.

TJ_Joe 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






All times are GMT -5. The time now is 10:54 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.1
User Alert System provided by Advanced User Tagging v3.1.0 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

Jeepģ, Wrangler, Liberty, Wagoneer, Cherokee, Gladiator, Mopar and Grand Cherokee are copyrighted and trademarked to FCA US LLC.
Wranglerforum.com is not in any way associated with FCA US LLC.