Gear ratio confusion - JeepForum.com
 8Likes
Reply
 
LinkBack Thread Tools
post #1 of 23 Old 11-12-2019, 06:17 PM Thread Starter
siilverback68
Registered User
 
siilverback68's Avatar
1987 YJ Wrangler 
 
Join Date: Jun 2019
Posts: 21
Gear ratio confusion

I am confused. I took apart my front end and the ring and pinion are pitted badly and needs to be replaced. Going off the tooth count I have a 3.54 gear ratio. 46 teeth on ring and 13 on pinion. Is this the same as 3.55 gears? I am looking at replacement ring and pinion and the teeth count is different. According to the specs of some of the replacement sets I am looking at the teeth count is 39/11 which is still 3.54. Will the different teeth count make a difference on fitment? I have a 87 YJ with a 4.2 and putting a AX15 into it.

siilverback68 is offline  
Sponsored Links
Advertisement
 
post #2 of 23 Old 11-12-2019, 08:21 PM
NHfireLJ
Web Wheeler
 
NHfireLJ's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2009
Location: Seacoast NH
Posts: 6,952
3.54 is numerically the same as 3.55

as long as the ratio is the same, they are all interchangable

AUDREY...95 YJ UNLIMITED LS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


LUCY...2005 Unlimited "LJ" Rubicon Sahara #495
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
SOLD

BETTY...94, Stroker 4.6,35"s, SOLD


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
style intake
NHfireLJ is offline  
post #3 of 23 Old 11-12-2019, 08:35 PM
80cj
Web Wheeler
 
80cj's Avatar
1980 CJ5 
 
Join Date: May 2002
Location: Hawaii
Posts: 7,755
Whatever 3.54 or 3.55 set you decide on, be sure the ring and pinion have matching numbers to show that they are a matched gear set.
80cj is offline  
 
post #4 of 23 Old 11-12-2019, 08:37 PM
NHfireLJ
Web Wheeler
 
NHfireLJ's Avatar
1995 YJ Wrangler 
 
Join Date: Dec 2009
Location: Seacoast NH
Posts: 6,952
Quote:
Originally Posted by 80cj View Post
46/11 is a 4.18 gear ratio. Actually, unheard of or at least not a common ratio.
Re-read it. He never said 46 by 11

AUDREY...95 YJ UNLIMITED LS
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


LUCY...2005 Unlimited "LJ" Rubicon Sahara #495
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
SOLD

BETTY...94, Stroker 4.6,35"s, SOLD


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
style intake
NHfireLJ is offline  
post #5 of 23 Old 11-12-2019, 10:09 PM
CSP
Registered User
 
Join Date: Aug 2002
Location: Colorado
Posts: 17,029
As long as the ratios are within 1% of each other, you're fine. Those two are only 0.007 gear ratio points apart, or 0.2%.

Many 1970s Ford trucks left the factory with 3.50 in the rear axle and 3.54 in the front.
Randonexplosion likes this.
CSP is offline  
post #6 of 23 Old 11-12-2019, 11:32 PM
80cj
Web Wheeler
 
80cj's Avatar
1980 CJ5 
 
Join Date: May 2002
Location: Hawaii
Posts: 7,755
Quote:
Originally Posted by NHfireLJ View Post
Re-read it. He never said 46 by 11
I know. I screwed up and corrected my post.
NHfireLJ likes this.
80cj is offline  
post #7 of 23 Old 11-13-2019, 06:52 AM
Siva283
Registered User
 
Siva283's Avatar
1993 YJ Wrangler 
 
Join Date: May 2011
Location: Baltimore
Posts: 4,683
Also you know its not as easy as just bolting the new stuff on right?
New gears new set up. While not hard its not easy either and requires special tools

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
Siva283 is online now  
post #8 of 23 Old 11-13-2019, 10:33 AM
Waternut
Web Wheeler
 
Waternut's Avatar
1988 YJ Wrangler 
 
Join Date: Sep 2016
Location: Macon
Posts: 1,022
Quote:
Originally Posted by siilverback68 View Post
I am confused. I took apart my front end and the ring and pinion are pitted badly and needs to be replaced. Going off the tooth count I have a 3.54 gear ratio. 46 teeth on ring and 13 on pinion. Is this the same as 3.55 gears? I am looking at replacement ring and pinion and the teeth count is different. According to the specs of some of the replacement sets I am looking at the teeth count is 39/11 which is still 3.54. Will the different teeth count make a difference on fitment? I have a 87 YJ with a 4.2 and putting a AX15 into it.
I'd like to see pictures. You'll probably be a minimum of $400 in parts to replace those gears and if you have a shop do the work, add another $500-$600 because it's a time consuming job. If you do it yourself, you'll probably be a couple hundred into special tools that you may or may not have and will have very limited use in other applications.

There are definitely smarter, easier, and cheaper ways to fix common gear ratio problems including a used axle. Sounds like more work but I promise you that swapping in a used axle and changing out any bad parts is WAY easier.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Waternut is offline  
post #9 of 23 Old 11-13-2019, 10:38 AM
fishadventure
Registered User
 
fishadventure's Avatar
1989 YJ Wrangler 
 
Join Date: Jul 2013
Location: Morrisville
Posts: 6,755
Garage
Quote:
Originally Posted by Siva283 View Post
Also you know its not as easy as just bolting the new stuff on right?
New gears new set up. While not hard its not easy either and requires special tools
He’s in Florida-

He could throw me a couple hundred and a spare bedroom for a week and I’ll drive down and do it for him... more than 50% serious here lol

[size=“3”]Shackles & D-rings are different things.
Cranking IS turning over
fishadventure is offline  
post #10 of 23 Old 11-13-2019, 11:30 AM
Siva283
Registered User
 
Siva283's Avatar
1993 YJ Wrangler 
 
Join Date: May 2011
Location: Baltimore
Posts: 4,683
Quote:
Originally Posted by fishadventure View Post
He’s in Florida-

He could throw me a couple hundred and a spare bedroom for a week and I’ll drive down and do it for him... more than 50% serious here lol
Well **** if we are going that route I would do it for the spare room and air fair

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Quote:
Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Quote:
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Quote:
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Quote:
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
Siva283 is online now  
post #11 of 23 Old 11-13-2019, 01:07 PM
1project2many
Registered User
1995 YJ Wrangler 
 
Join Date: Oct 2018
Location: Lakes Region
Posts: 343
My first job as a mechanic was learning to overhaul gearboxes and axles way back in 1987. I still do it on the side. The tools I use for R&P replacements include:

Small hammer
Medium hammer
Selection of various diameter exhaust tubing
Cutoff wheel
Chisel
10" drift
Bronze Punch
Prick punch
Set of "setup" bearings w/ ID honed
Pile of shims collected over the years
Dial indicator
Ring gear marking compound / white grease
Combination wrenches
Pry bar
Torque Wrench

The absolutely most important part of R&P replacement is cleaning. If the R&P or bearings are bad expect to spend 2-3 hours cleaning. Not clean = parts failure.
Boojo35 likes this.
1project2many is offline  
post #12 of 23 Old 11-14-2019, 06:23 PM Thread Starter
siilverback68
Registered User
 
siilverback68's Avatar
1987 YJ Wrangler 
 
Join Date: Jun 2019
Posts: 21
Quote:
Originally Posted by Waternut View Post
I'd like to see pictures. You'll probably be a minimum of $400 in parts to replace those gears and if you have a shop do the work, add another $500-$600 because it's a time consuming job. If you do it yourself, you'll probably be a couple hundred into special tools that you may or may not have and will have very limited use in other applications.

There are definitely smarter, easier, and cheaper ways to fix common gear ratio problems including a used axle. Sounds like more work but I promise you that swapping in a used axle and changing out any bad parts is WAY easier.
Which photos would you like? I have a friend who has an entire shop. The only hard part is its currently not even a rolling frame. Going to take front axle off to take to his shop. You are not kidding about the prices. SO far the least expensive gears that are same ratio are about $330 and the master rebuild kit about another $150. The 3.55 gears for the Dana 30 are expensive. It would almost be same cost to switch out both front and back to a higher gear ratio.
siilverback68 is offline  
post #13 of 23 Old 11-14-2019, 09:33 PM
Waternut
Web Wheeler
 
Waternut's Avatar
1988 YJ Wrangler 
 
Join Date: Sep 2016
Location: Macon
Posts: 1,022
I was looking for pictures of the pitting in the gears. The thought process was if it's not too bad, you just roll with the pitted gears until they fail because you aren't really going to tear much else up if you do. For $300, you should be able to just buy a whole new axle and bolt it in. This option is very viable especially if you're already talking about taking the axle to a shop.

The price and procedure is the same whether you swap in 3.55 gears or 4.88.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Waternut is offline  
post #14 of 23 Old 11-15-2019, 06:43 PM Thread Starter
siilverback68
Registered User
 
siilverback68's Avatar
1987 YJ Wrangler 
 
Join Date: Jun 2019
Posts: 21
Here are the photos.
Attached Images
     
siilverback68 is offline  
post #15 of 23 Old 11-15-2019, 06:45 PM Thread Starter
siilverback68
Registered User
 
siilverback68's Avatar
1987 YJ Wrangler 
 
Join Date: Jun 2019
Posts: 21
Quote:
Originally Posted by Waternut View Post
I was looking for pictures of the pitting in the gears. The thought process was if it's not too bad, you just roll with the pitted gears until they fail because you aren't really going to tear much else up if you do. For $300, you should be able to just buy a whole new axle and bolt it in. This option is very viable especially if you're already talking about taking the axle to a shop.

The price and procedure is the same whether you swap in 3.55 gears or 4.88.
I did not think of a new axle. What would you suggest? I also appreciate the offers of room and board to switch it out for me. Unfortunately I am not sure any of my kids would give up their room.
siilverback68 is offline  
Reply

Tags
gear change , pinion , ring and pinion

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











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



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