How to find gear ratio of front Clamshell

Bought my truck used, has always had this wierd issue where the steering wheel really fights me whenever in 4wd, tires are new alignment is dead on, acts even worse when in 4wd on pavement....

The previous owner told me he had put a third member out of a 1st gen because it had the same gears as this truck (4.10) when his third went out because he messed with pinion bearing. (Stock gears I believe were 3.73 but he said it had been re geared to 4.10)

Now Im thinking that the gear ratios are off front to back.

I am in the middle of converting from a Drop bracket lift to TC +2 long travel and SUA in rear, Front clamshell is sitting on my workbench, CVs removed... what is the easiest way to find gear ratio?

Might be a dumb question, my brain is kind of numb after ~30 hours so far into this project in 100 degree + weather

 

Not sure if you have the differential open so you can visually count your gearing ?
Lets say the Large crown gear has 41 teeth , and the small pinion gear has 11
Divide 41 into 11 . this equals 3.7 ........................3.70 gear ratio

 

No, was kind of trying to avoid splitting the clamshell if possible... was hoping to be able to maybe spin yoke, and watch the little piece CV attaches to (I can see it spin while spinning yoke) Just wasn't sure how the numbers "add up" after that (or divide out rather?) to get the gear ratio

And thank you for the response!

 

OK , I get it .
Mark the driveshaft yoke and mark the flange where the axle mounts up with a crayon.
Slowly spin the drive yoke 3 times counting the revolutions of both marks ,then divide the revolutions .
3.7 turns of the input shaft to almost 3 turns of the output equals 3.70 ratio . This is a highway diff
11 turns of input shaft to almost 4 turns of the output equals 4 :11 . This is designed for off road .
Differential System: Precaution, Parts Location
Differential System: System Diagram, Problem Symptoms Table
Differential System: On-Vehicle Inspection, Inspection
Differential Oil: Adjustment
Rear Differential Carrier Oil Seal: Removal
Rear Differential Carrier Oil Seal: Installation
Differential Side Gear Shaft Oil Seal (For 4WD): Removal, Installation
Front Differential Carrier Assembly (For 4WD): Components
Front Differential Carrier Assembly (For 4WD): Removal, Disassembly, Reassembly
Front Differential Carrier Assembly (For 4WD): Installation
Rear Differential Carrier Assembly: Components
Rear Differential Carrier Assembly: Removal, Disassembly, Reassembly
Rear Differential Carrier Assembly: Installation
Rear Differential Carrier Assembly (w/ Differential Lock): Components
Rear Differential Carrier Assembly (w/ Differential Lock): Removal, Disassembly
Rear Differential Carrier Assembly (w/ Differential Lock): Inspection, Reassembly, Installation
Differential Lock System: Parts Location
Differential Lock System: System Diagram, On-Vehicle Inspection, Inspection

 

Exactly the info I needed.. Thank you!

 

I was backwards LMAO

3.7 turns of the input shaft to almost 3 turns of the output equals 3.70 ratio . This is a highway diff
11 turns of input shaft to almost 4 turns of the output equals 4 :11 . This is designed for off road .

 

http://www.how-to-build-hotrods.com/gear-ratio.html

 

Read the link that Bill posted and ignore everything else in this thread. For your purposes, treat this as if it is a posi. There won't be enough resistance to spin the spider gears. So, count the number of turns of the pinion yoke to make the splined part where the CV joint goes, turn exactly 1 turn.

Example 4 1/8 turns = 4.10

The numbers actually mean 4.10 to 1 ratio. In other words it takes a little over 4 turns of the driveshaft to make a tire go around once.

 

Ok, but why is 4 1/8 = 4.10? Would it not be 4 1/10 = 4.10?

 

Heisenberg's Uncertainty Principle

 

OK, technically, yes, but it's going to be pretty difficult to eyeball 1/10th of a turn. You're talking a difference of only 9 degrees. So, 1/2 turn, whole turn, 1 1/2 turns, 2 turns, etc... then not quite 1/2 of a 1/4 turn. Using the rotate and count method, you need to know what the available ratios are. 4 and a little bit is going to be a very obvious difference from 3 3/4 turns or 4 1/2 turns.

 

Definitely... Looks like the previous owner messed up... Front diff was 3.73 and he put a rear 3rd member geared 4.10... I just ordered a front carrier assembly with 4.10 gears out of a 2010 4x4 4 cylinder... assuming it will all bolt up should be good to go.