different gear ratio front and rear - JeepForum.com

Reply
 
LinkBack Thread Tools
post #1 of 23 Old 06-02-2007, 01:19 AM Thread Starter
keecho
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: CA
Posts: 88
different gear ratio front and rear

hey fellas
I just figured out that I have diffrent gear ratios in front and rear diff's. How can I tell whats in what? I have a 2004 tj with i6 and 5spd. its a jeep I just purchased last week but it wasnt in driving condition then so I could not test the 4wd.
any id tags or sn #'s I can look at to tell whats in what. I believe I have a 2002 front diff and the rear is the stock 2004. please help
Jack

keecho is offline  
Sponsored Links
Advertisement
 
post #2 of 23 Old 06-02-2007, 01:29 AM
dougolupski
It's Heep not Jeep
2007 JK Wrangler 
 
Join Date: Dec 2004
Location: Santa Barbara
Posts: 654
Well I wouldn't trust the tags on the diff cover the gears can be changed and the tags left on. Your two best bets would be pull the covers off and check the number ratio stamped on the gear. While it works most of the time on factory gears they sometimes don't have a ratio on it just a part number. The other option would be to put you transfer case in neutral and one at a time lift the front and rear. Once you have one up in the air rotate a tire around one full rotation and count the number of times the drive shaft spins. It's best to mark your wheel and driveshaft with something. Example if I rotate my tire around and my driveshaft spins four and a half times I have 4.55 gears. It gets a real good guess of what you have.

What part of Cali are you in?

Jeep: 07 Wrangler X 2DR Black
Crime Guard Alarm with 2way pager, AFE CAI, DynaPro Exhuast
M.O.R.E. Body Lift, Source Co2 Tank, Stubbied Stock Front Bumper
KMC XD 795 Hoss Black 17" wheels and Maxxis Bighorn 305/70/17 tires
Every mod in the write up section.

Old Jeep: 04 Wrangler X Yellow Built To The Hilt For Three Great Years.

POLISH JEEP OWNERS CLUB #2
dougolupski is offline  
post #3 of 23 Old 06-02-2007, 01:50 AM Thread Starter
keecho
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: CA
Posts: 88
thanks for explaning it to me I will jack it up tommorow mornin.
Im in Pasadena CA

Jack
keecho is offline  
post #4 of 23 Old 06-02-2007, 10:24 AM
Jerry Bransford
Administrator
 
Jerry Bransford's Avatar
2004 TJ Wrangler 
 
Join Date: Jan 2003
Location: Escondido, California
Posts: 65,781
What leads you to believe it has a different f/r axle ratio? A .01 difference in f/r axle ratios is normal except for the Rubicon only because it has matched D44 f/r axles.

Getting Savvy...

When you have a choice, buy American.
Jerry Bransford is online now  
post #5 of 23 Old 06-02-2007, 10:52 AM Thread Starter
keecho
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: CA
Posts: 88
Thanks for your help guys
I did find tags on the diff's
the back for sure is 3-07
and from what I can make out the front is a 4-10? front looks like an older diff housing because the tag was rusted out and the front axle just looks older vs the rear axle .

anyway if I go 33's Im guessing keep the 4-10's? and swap out the back?

Jack
keecho is offline  
post #6 of 23 Old 06-02-2007, 10:57 AM
Jerry Bransford
Administrator
 
Jerry Bransford's Avatar
2004 TJ Wrangler 
 
Join Date: Jan 2003
Location: Escondido, California
Posts: 65,781
Ok, just verify that they truly are different ratios before doing anything else. You can set the axles on jack stands and after shifting the t-case into neutral, rotate a tire on each axle and carefully note the number of driveshaft revolutions. If they're the same or within a tenth of a rotating the same, you're golden.

Getting Savvy...

When you have a choice, buy American.
Jerry Bransford is online now  
post #7 of 23 Old 06-02-2007, 11:02 AM Thread Starter
keecho
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: CA
Posts: 88
what kind of axle comes with my jeep? do I have a dana 35 in the back and dana 30 in the front? what is suppose to be there?

Jack
keecho is offline  
post #8 of 23 Old 06-02-2007, 11:05 AM
Jerry Bransford
Administrator
 
Jerry Bransford's Avatar
2004 TJ Wrangler 
 
Join Date: Jan 2003
Location: Escondido, California
Posts: 65,781
Definitely a Dana 30 up front and likely a Dana 35c in back, though it's possible it has the optional better/stronger Dana 44 in the rear.

If the rear axle has an oval-shaped differential cover with a black plastic lubricant hole plug, it's a Dana 35c. If the cover is more stopsign-shaped with a steel bolt in the lube fill hole, it's a Dana 44.

Getting Savvy...

When you have a choice, buy American.
Jerry Bransford is online now  
post #9 of 23 Old 06-02-2007, 11:11 AM
otisdog
Registered User
2008 WK 
 
Join Date: Apr 2005
Location: Aurora Co
Posts: 4,683
They come with a D35 or D44 in the rear and a D30 in the front.
A 4.10 front D30 would have come out of a 4-banger manual tranny Jeep.
Yes - if the front is 4.10 and the rear is 3.07 do something with the rear.
You may want to upgrade the rear at the same time. Take note that Rubicons have 4.11 gears so maybe just look for a Rubi rear axle which would be a D44 [ much stronger than the 35] and would also have an air locker.
The D35 is not worth putting money into if you plan on 4-wheeling. The other option for it would be a Super 35 kit and regear to 4.11.
As said make sure you have the mismatch before you do anything.
Jim

08 Grand Cherokee Overland
otisdog is offline  
post #10 of 23 Old 06-02-2007, 11:55 AM
nitecop
Registered User
1999 TJ Wrangler 
 
Join Date: Jun 2005
Location: midwest
Posts: 4,555
Quote:
Originally Posted by otisdog
Yes - if the front is 4.10 and the rear is 3.07 do something with the rear.
You may want to upgrade the rear at the same time. Take note that Rubicons have 4.11 gears so maybe just look for a Rubi rear axle which would be a D44 [ much stronger than the 35] and would also have an air locker.
The D35 is not worth putting money into if you plan on 4-wheeling.
As said make sure you have the mismatch before you do anything.
Jim
This sound like a good plan.

Jim
USW, OAPSE Union member
99 TJ Sahara 4.0 5-Sp FUV + farm worker
Project f-Xj F150/XJ Ford eXtreme jeep combo
06 6 Speed LJ my daily driver.
Colorado Jeep club memeber #505
nitecop is online now  
post #11 of 23 Old 06-02-2007, 03:03 PM Thread Starter
keecho
Registered User
2004 TJ Wrangler 
 
Join Date: May 2007
Location: CA
Posts: 88
how much money would a dana 44 rear cost if I find one at a jeep junk yard or somthing? what should I be expecting to pay?

Thanks for all the good help
Jack
keecho is offline  
post #12 of 23 Old 06-02-2007, 05:02 PM
WilliamH
Registered User
 
Join Date: Aug 2006
Location: Farmington
Posts: 248
There's one problem with the suggestion to rotate one tire and count driveshaft revolutions: spider gears.

It should work on a limited slip differential if the clutches are okay (probably limited slip on the rear).

But on an open diff (like the front should be), it woudn't likely work, because the spider gears would most likely turn. I would remove the cover to be sure.

'06 Toyota Tacoma TRD Double cab with selectable rear locker ('06 Wrangler replacement).
'08 Yamaha FJR1300 sport/touring motorcycle with ABS and power adjustable windshield.
'06 Yamaha Wolverine 450 sport/4wd ATV.
'09 Yamaha Grizzly 550 SE with EPS, winch.
WilliamH is offline  
post #13 of 23 Old 06-02-2007, 09:19 PM
dougolupski
It's Heep not Jeep
2007 JK Wrangler 
 
Join Date: Dec 2004
Location: Santa Barbara
Posts: 654
No it works on a open as well, though sometimes you have to put tension on the other wheel to get the DS to rotate. I agree with what everyone said above, it's right on the money. As far as junk yard price for a direct drop in TJ model count on 500.00 or a little more. I bought a TJ d44 housing and it cost me 300 buck just for the used housing alone. The other two options would be to buy an XJ housing than have someone welding on the brackets but it will cost around 400.00 bucks or more to do that. The best way I see from my own experience would be to buy a complete d44 housing with gears and new internals pre made ready to drop in. You can find them at all the major retailers from 1000.00 on up. I know how to do gears but with all the time I spent along with buying all the parts it would have been cheaper in the long run to just buy a complete unit.

Jeep: 07 Wrangler X 2DR Black
Crime Guard Alarm with 2way pager, AFE CAI, DynaPro Exhuast
M.O.R.E. Body Lift, Source Co2 Tank, Stubbied Stock Front Bumper
KMC XD 795 Hoss Black 17" wheels and Maxxis Bighorn 305/70/17 tires
Every mod in the write up section.

Old Jeep: 04 Wrangler X Yellow Built To The Hilt For Three Great Years.

POLISH JEEP OWNERS CLUB #2
dougolupski is offline  
post #14 of 23 Old 01-06-2010, 04:32 PM
mrriceguyrj
Registered User
2006 LJ Wrangler 
 
Join Date: Jan 2010
Location: Reno
Posts: 26
I'm going to ask instead of starting a new thread that will discuss the same stuff, does it effect anything to have a different gear ratio in front and rear?

I just recently picked up a '00 2.5L with 32"-33" tires on it, it has stock 4.10 gears installed, but the guy included 4.88 gears for the rear (not installed), and I'm trying to figure out if I should have the rear installed and keep the front at 4.10? This is an every-day driver mainly on streets and 2wd.
mrriceguyrj is offline  
post #15 of 23 Old 01-06-2010, 04:35 PM
biffgnar
Moderator
 
biffgnar's Avatar
2006 TJ Wrangler 
 
Join Date: May 2008
Location: Westchester, NY
Posts: 20,195
Quote:
Originally Posted by mrriceguyrj View Post
does it effect anything to have a different gear ratio in front and rear?
It destroys your transfer case!

#LetGaryDebate
biffgnar is online now  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Gear ratio front and back check... 88YJtoCJ YJ Wrangler Technical Forum 5 03-02-2011 05:02 PM
what rear end gear ratio would be ideal Mark05059 YJ Wrangler Technical Forum 9 01-04-2010 11:59 AM
How do I find out what rear axle and gear ratio I have Breacher631 YJ Wrangler Technical Forum 5 03-06-2009 05:20 PM
rear gear ratio, is this possible dannyv6 TJ Wrangler Technical Forum 13 05-11-2008 09:40 PM
rear end gear ratio issues badoosh27 TJ Wrangler Technical Forum 2 06-13-2005 06:24 AM

Posting Rules  
You may post new threads
You may 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 On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome