How to tell gear ratio by counting teeth - Ford Powerstroke Diesel Forum
User Tag List

Reply
 
LinkBack Thread Tools Display Modes
post #1 of 14 Old 04-24-2013, 03:44 PM Thread Starter
Compression Ignition Addict
 
7.3 on 40s's Avatar
 
Join Date: Oct 2012
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
How to tell gear ratio by counting teeth

Doing some differential work i thought it might be nice to know what gear ratio i have since the sticker with the axle code has peeled and blown away. Searched and found a differential co. online that stated, well in my case if i have a count of 41 on the ring gear and 9 on the pinion that i have 4.56 gears. Does this sound right?

On another note they stated ideal backlash on the ring gear when shimming up the carrier is .010 Is this correct?

97 F350 XLT CC LB 4x4 7.3psd 5spd White/Tan
-Straight Piped
-6637 Intake
-8in. Lift
-Welds w/40in. Rockers
-Warn hubs
-LSD w/4.56 gears
-Leather bucket seats
-Rhino lined
7.3 on 40s is offline  
post #2 of 14 Old 04-24-2013, 03:50 PM
Compression Ignition Addict
 
boozinag's Avatar
 
Join Date: Apr 2012
Location: Texas
Posts: 705
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
no tag on the diff with the ratio? it'll be 3.55s or 4.10s.

Gerry

'97 CCSB f-250 4x4 auto, 6pos chip w/ canned tunes, AFE intake, 4 in exhaust, 3in dp, 3.55 gears,
Dana 60 rebuilt and waiting to be installed
184k
boozinag is offline  
post #3 of 14 Old 04-24-2013, 04:14 PM Thread Starter
Compression Ignition Addict
 
7.3 on 40s's Avatar
 
Join Date: Oct 2012
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Ill try and find the site i was on that seemed like it had all the numbers and ways to figure out what gearing you have. 41 ring and 10 pinion are 4.10s and 41-11 are 3.73s. My gears are aftermarket and never asked the PO what ratio. Ill find the site i found this info. on and post back.

97 F350 XLT CC LB 4x4 7.3psd 5spd White/Tan
-Straight Piped
-6637 Intake
-8in. Lift
-Welds w/40in. Rockers
-Warn hubs
-LSD w/4.56 gears
-Leather bucket seats
-Rhino lined
7.3 on 40s is offline  
post #4 of 14 Old 04-24-2013, 04:16 PM Thread Starter
Compression Ignition Addict
 
7.3 on 40s's Avatar
 
Join Date: Oct 2012
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
drivetrain.com

97 F350 XLT CC LB 4x4 7.3psd 5spd White/Tan
-Straight Piped
-6637 Intake
-8in. Lift
-Welds w/40in. Rockers
-Warn hubs
-LSD w/4.56 gears
-Leather bucket seats
-Rhino lined
7.3 on 40s is offline  
post #5 of 14 Old 04-24-2013, 04:25 PM
Compression Ignition Addict
 
boozinag's Avatar
 
Join Date: Apr 2012
Location: Texas
Posts: 705
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I would be curious to know what gears were installed.

Gerry

'97 CCSB f-250 4x4 auto, 6pos chip w/ canned tunes, AFE intake, 4 in exhaust, 3in dp, 3.55 gears,
Dana 60 rebuilt and waiting to be installed
184k
boozinag is offline  
post #6 of 14 Old 04-24-2013, 04:53 PM
Serving Our Country!
 
JSchuricht's Avatar
 
Join Date: Aug 2007
Location: Manor, TX
Posts: 2,968
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 25 Times in 24 Posts
Feedback Score: 2 reviews
If you still have the gears in the axle, just spin it by hand and count the revolutions between the pinion and ring.

JSchuricht is offline  
post #7 of 14 Old 04-24-2013, 05:11 PM
Compression Ignition Addict
 
Join Date: Aug 2008
Location: Madison, WI
Posts: 3,851
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 29 Post(s)
Thanks: 4
Thanked 126 Times in 122 Posts
Feedback Score: 0 reviews
Um, just divide the number of ring teeth by the number of pinion teeth....
madpogue is offline  
post #8 of 14 Old 04-24-2013, 05:15 PM
Compression Ignition Addict
 
boozinag's Avatar
 
Join Date: Apr 2012
Location: Texas
Posts: 705
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Is it really that simple?!?!?

Gerry

'97 CCSB f-250 4x4 auto, 6pos chip w/ canned tunes, AFE intake, 4 in exhaust, 3in dp, 3.55 gears,
Dana 60 rebuilt and waiting to be installed
184k
boozinag is offline  
post #9 of 14 Old 04-24-2013, 05:16 PM
Compression Ignition Addict
 
OL' OutLaw's Avatar
 
Join Date: Jan 2011
Location: Suthren OryGun
Posts: 460
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I would be willing to bet you mis-counted the Pinion gear teeth...it's probably got 10 teeth, not nine.....

and yes, it's that simple..... just divide the ring gear tooth count by the pinion gear tooth count....

41 divided by 9 = 4.5555555555

41 divided by 10 = 4.1

etc....

'97 Centurion. F350 4x4 CCLB
Full Force 180cc Stage I's, D66, SRP-1.1, ARP, Banks IC, DIY E-Fuel, EBPV Del & Gut'd Ped., BD Exhaust Brake., SD IDM, HPX, BstFoolr, 4" DP - 4" exh,
6.0 Fan, 180 T-Stat, DIY Don.105006 AF, CCV Mod, BTS, W/ SD Trans Lines, Tru-Cool Max, PML Trans Pan, Bumper Mod, IssPro Gauges, Fluidampr, Mellings LPOP.....
Tuned by "The WildMan".
OL' OutLaw is offline  
post #10 of 14 Old 04-24-2013, 05:22 PM Thread Starter
Compression Ignition Addict
 
7.3 on 40s's Avatar
 
Join Date: Oct 2012
Posts: 170
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Counted again. Marking 1st tooth with paint. 41 and 9. 4.56 it is. sweeeet.

97 F350 XLT CC LB 4x4 7.3psd 5spd White/Tan
-Straight Piped
-6637 Intake
-8in. Lift
-Welds w/40in. Rockers
-Warn hubs
-LSD w/4.56 gears
-Leather bucket seats
-Rhino lined
7.3 on 40s 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