Rear Diff. Question for 3.73 ratio - Ford Powerstroke Diesel Forum
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 11 Old 01-01-2012, 11:17 PM Thread Starter
Member
 
350DingBat's Avatar
 
Join Date: Jan 2009
Posts: 35
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Talking Rear Diff. Question for 3.73 ratio

Hi guys,

I need to see about getting some lower gears for my diffs.

I run Toyo M/T's 38x15.5x20, with D1 (3.37) diff. gears.

What ratio would you guys recommend? (4.10, 4.30???)

I do a fair amount of towing, and this ratio, plus my large tire size, is KILLING my power!
She dogs on the bigger hills thats for sure.

Any and all opinions are welcomed.
Thanks guys.
350DingBat is offline  
post #2 of 11 Old 01-03-2012, 07:19 PM Thread Starter
Member
 
350DingBat's Avatar
 
Join Date: Jan 2009
Posts: 35
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Wow...

25 people have looked at this thread and NOBODY can give me a suggestion?!?!

Is anyone running a setup like mine?
350DingBat is offline  
post #3 of 11 Old 01-05-2012, 05:29 PM
Member
 
Tom Hartz's Avatar
 
Join Date: Sep 2010
Location: Santa Clarita, Ca.
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Based on my Jeep experience this is what I see.

First tale a look at this. Gear Ratio from Tire Size

I am not sure what tire size your truck came with, so I guessed at 32" tall. Now running a 38" tire it looks like you should be running a 4.30 ratio.

Double check the numbers on the Currie Calculator.

Tom
Tom Hartz is offline  
post #4 of 11 Old 01-05-2012, 05:37 PM
Serving Our Country!
 
JSchuricht's Avatar
 
Join Date: Aug 2007
Location: Manor, TX
Posts: 2,975
Thanks: 0
Thanked 27 Times in 26 Posts
Mentioned: 1 Post(s)
Quoted: 0 Post(s)
Feedback Score: 2 reviews
4.30 would put you close to stock.

JSchuricht is offline  
post #5 of 11 Old 01-05-2012, 05:53 PM
Member
 
Tom Hartz's Avatar
 
Join Date: Sep 2010
Location: Santa Clarita, Ca.
Posts: 40
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Quote:
Originally Posted by JSchuricht View Post
4.30 would put you close to stock.
That is the same I was thinking. It should be good. Just remember even if you go with 4.30s you still have a much bigger tire to get rolling and stop. It will never feel like it did stock.
Tom Hartz is offline  
post #6 of 11 Old 01-05-2012, 11:09 PM
Compression Ignition Addict
 
GregsSD's Avatar
 
Join Date: Mar 2008
Location: Santa Rosa, CA
Posts: 1,371
Thanks: 0
Thanked 5 Times in 5 Posts
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
Garage
Feedback Score: 0 reviews
I run 4.30's with my 35's and it works great.
4.10 is not worth going to because it is not much change from 3.73, so go to at least 4.30, or even 4.56 if you really want some good towing power!

2005 F-250 CC/SB 4x4 medium wedgewood blue

5" lift, 5" Donahoe rear springs, 35x13.50 MTZ's, 18x12 Fuel Hostage wheels, 4.30 gears, Banks 4" exhaust, Airraid intake, SCT from Innovative, ARP headstuds, Bulletproof ficm, Scangauge II, Randy Ellis Design lightbar, Street Scene flares, Harpoon mod, Zoodad mod, LED 2010 taillights, Switchback LED front turn signals
GregsSD is offline  
post #7 of 11 Old 01-06-2012, 11:14 AM
Member
 
z28gsxr's Avatar
 
Join Date: Dec 2009
Location: Los Angeles
Posts: 77
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Quote:
Originally Posted by GregsSD View Post
I run 4.30's with my 35's and it works great.
4.10 is not worth going to because it is not much change from 3.73, so go to at least 4.30, or even 4.56 if you really want some good towing power!
What kind of MPG do you get with the 4.30? I have a similar set up to the OP but have toyo All Terrains in a 37/14/18

As it is now i get roughly 14mpg. Mine doesn't struggle too bad in the uphills since i really don't tow more than like 7k but more power would not hurt. My truck only has a 4" turbo back and a k&n ram air intake as far as power mods go. Tuner is in the plans. Would it be best to get the tuner or the gearing first?

02 F250 7.3L 4x4
z28gsxr is offline  
post #8 of 11 Old 01-06-2012, 05:39 PM
Compression Ignition Addict
 
GregsSD's Avatar
 
Join Date: Mar 2008
Location: Santa Rosa, CA
Posts: 1,371
Thanks: 0
Thanked 5 Times in 5 Posts
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
Garage
Feedback Score: 0 reviews
If you do the gears first, it will take alot of strain off of your tranny so it should last longer!

I get about 14 mpg, but I drive very little highway miles, it's all in town and backroads. Changing gears brought back about half the mileage that I lost by going to 35's.

2005 F-250 CC/SB 4x4 medium wedgewood blue

5" lift, 5" Donahoe rear springs, 35x13.50 MTZ's, 18x12 Fuel Hostage wheels, 4.30 gears, Banks 4" exhaust, Airraid intake, SCT from Innovative, ARP headstuds, Bulletproof ficm, Scangauge II, Randy Ellis Design lightbar, Street Scene flares, Harpoon mod, Zoodad mod, LED 2010 taillights, Switchback LED front turn signals
GregsSD is offline  
post #9 of 11 Old 01-06-2012, 08:23 PM
Member
 
z28gsxr's Avatar
 
Join Date: Dec 2009
Location: Los Angeles
Posts: 77
Thanks: 0
Thanked 0 Times in 0 Posts
Mentioned: 0 Post(s)
Quoted: 0 Post(s)
Feedback Score: 0 reviews
Quote:
Originally Posted by GregsSD View Post
If you do the gears first, it will take alot of strain off of your tranny so it should last longer!

I get about 14 mpg, but I drive very little highway miles, it's all in town and backroads. Changing gears brought back about half the mileage that I lost by going to 35's.
If you don't mind me asking, what did it cost for the gears and installation for both differentials?
z28gsxr is offline  
post #10 of 11 Old 01-06-2012, 09:10 PM
Compression Ignition Addict
 
GregsSD's Avatar
 
Join Date: Mar 2008
Location: Santa Rosa, CA
Posts: 1,371
Thanks: 0
Thanked 5 Times in 5 Posts
Mentioned: 0 Post(s)
Quoted: 1 Post(s)
Garage
Feedback Score: 0 reviews
Quote:
Originally Posted by z28gsxr View Post
If you don't mind me asking, what did it cost for the gears and installation for both differentials?

Gears, Bearings, and labor was around $1700-$1800

2005 F-250 CC/SB 4x4 medium wedgewood blue

5" lift, 5" Donahoe rear springs, 35x13.50 MTZ's, 18x12 Fuel Hostage wheels, 4.30 gears, Banks 4" exhaust, Airraid intake, SCT from Innovative, ARP headstuds, Bulletproof ficm, Scangauge II, Randy Ellis Design lightbar, Street Scene flares, Harpoon mod, Zoodad mod, LED 2010 taillights, Switchback LED front turn signals
GregsSD is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Ford Powerstroke Diesel Forum 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 email 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.



Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



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 On
Pingbacks are On
Refbacks are On

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